Beginner's Guide

Thanks to Amidatelion for writing this guide!

This isn't meant to be a complete guide to everything about BTA. It's meant to provide training wheels for new players as they try to do sick jumps off the learning curve and a helmet for when that inevitably goes wrong.

Differences from Vanilla

Permanent Evasion: Evasion can no longer be reduced by firing at targets. This applies to both the player and the opfor. Only sensor lock and stability loss reduce evasion, though there are many more options to increase your accuracy.
Sprinting: You can now fire after sprinting, albeit with an accuracy penalty.
Pilot Behaviors: Pilots can panic, leading to them ejecting. Things that influence panic include being shot, being flanked and being the only pilot left in a lance.
Pilot Injuries. When a pilot is injured (either through a cockpit hit, falling over, losing a side torso etc.) on top of losing a pip of health they can suffer from dynamic injuries with different effects, including bleedouts (this kills the pilot... eventually). They can also be sent into battle with injuries, with obvious risks.
Positioning: Height matters, conferring a bonus to hit target below you and a penalty to hit targets higher up than you.
Size Delta: Larger 'mechs have difficulty hitting smaller 'mechs and smaller 'mechs have a bonus to hit larger ones. This confers a +/- bonus/penalty per 15 ton difference between the two 'mechs shooting at one another, to a maximum of +/- 5 bonus/penalty to accuracy.
Precision Strikes: Precision Strikes no longer allows targeting of individual components, instead conferring a flat bonus to hit. Called shots can be re-enabled by the rank 8 Gunnery skill Precision Master or certain Fire Control Systems.
Melee: A great many changes, but in brief: kicking and charging are now options. All weapons that are not AOE or that have a minimum range can fire in melee, but are limited by where on the mech they are. Weapons on arms cannot be used when punching, weapons on the legs (yes, that's a thing) cannot be used while kicking and no weapons fire on a charge.
ECM: ECM no longer makes you "invisible" and instead provides flat defense bonuses in an area. Alongside Guardian ECM there are a variety of options that confer defense, view range and sensor bonuses. These are those circles you will see under some mechs.
Mech Engineer: There are many, MANY more options available to you. Read the in-game descriptions carefully, but in brief:
- XL engines free up weight but kill the 'mech if a side torso is lost.
- Core sizes determine how fast you can go and how many bonus internal or required external heat sinks you can fit. Small engines require you to mount external heat sinks (but are free, weight-wise).
- Heat sink kits of various types must match the heat sinks you are trying to use.
- Armor types have weight and armor related effects but cost "dynamic slots" that are redistributed automatically around the mech.
Reworked skills: See them here.
Vehicles are scary, but have significant weak spots that can be exploited. There will be an entire section dedicated to this, don't worry.

Starting a New Career

Quick prep: on a new install, load the Skirmish mech bay - this is required to load all assets properly.

Difficulty settings

There are a few changes you can make to your starting settings that will ease your journey. I recommend these because as much as many people may want a tougher economic game, that often gets in the way of really coming to grips with the game's changed tactics and strategies - you can't figure out how you want to use heavies if you can never afford to get there. If you find you don't enjoy some of these options you can always change these later on in-game:

Reduced Argo costs: does what it says on the tin. Helpful for getting the basic upgrades out of the way early like increased drop size, mech bays and medic/moral points
Friendly Fire: For your first career it's strongly recommended that you set this to either Enemies Only or Disabled until you understand how godawful your initial accuracy is. When set to All you will at some point core one of your own 'mechs by accident unless you are very careful.
Starting Planet: Affects what 'mechs you're going to start with and what you're likely to fight. Some picks can drastically increase or decrease the difficulty of the early game so be careful. Safe bets are Steiner and Davion but any of the "standard" starts are good (except, arguably, for Arano, which is slightly harder). Please note the Funsies and Battle Armor starts and any other labelled as "Hard" are not kidding around, only play them if you want a challenge. For the complete lists of what 'mechs you can get in each start click here.
Parts for Assembly: 3-5 is reasonable. Anything beyond that and you're going to be limiting yourself of the chance to try out rarer 'mechs.
Mech Recovery: Chance to reclaim the ruined metal corpse of your mech. Leave as standard.
Contract/Salvage: Self-explanatory. We recommend leaving it as standard but adjust it up or down if you want an easier/harder game.
Commander Experience: It's worthwhile to increase this to 10,000 so you have a ringer with good accuracy. You can drop it down in later careers.
Advanced Mechwarriors: The rate at which you see those crazy pilots you can never hire because your rep is too low.
Pilots per system: Self-explanatory. Leave as standard.
Mechwarrior Progression/Exponent/Multiplier: Complicated math. Leaving it as standard is fine.
Lethality: This is lethality in regards to headshots and nothing else. Leave it on normal.
Starting money: Definitely worth bumping up as a newbie.
Mechbay C-bills: Complicated math. Leaving it as standard is fine.
Shop Selling Prices/Scrap Return: I actually recommend turning scrap as low as it can go and bumping selling prices up a bit. This encourages you to be careful and strategic in what you salvage and build - scrapping stuff turns into a real option of last resort. "Oh crap I'm about to go bankrupt" sort of things.
Mech Maintenance: Large cost increase. Leave it on Easy.

Commander Generation

There are a few new things going on here. The first is largely fluff but also dictates some changes to your starting stats, the second also adjusts your stats but more notably confers a unique minor boost to your Commander which you can check by hovering your mouse over the orange text in the bar to the right

Aerospace Pilot: gives the Commander a +5% sprint speed boost.
Bounty Hunter: gives the Commander a +1% chance to hit headshots.
Officer Trainee: gives the Commander bonus +2 resolve whenever resolve is gained (similar to how Comms Suites work).
Offroad Racer: gives the Commander +30 to their unsteady threshold.
Offworld Smuggler: gives the Commander a permanent +10% increase to their sensor range.
Special Operative: gives the Commander +2 accuracy when firing at maximum range.

The third, however, confers significant bonuses:

Pioneering Comrades: Grants BTA crew. Strong crew with unique skills. Kinda OP, but a very good choice starting out. Also, pay your respects. Some are more difficult to use than others. They have special skills, found in their respective pilot pages, in-game bios and in the buffs section of the combat UI.
Life Savings: Does what it says on the tin. Cash money and morale.
Great Reputation: Increase in base MRB score. Your worst choice. You're not ready.
Upengined Dropship: Unique Argo upgrade that decreases travel time between systems and a free pilot added to your barracks. While on the surface of it the increase in speed is minor it DOES pay out eventually in saved transport costs and it's worth noting it unlocks and Argo upgrade you can't get anywhere else. Tech points are super useful early on as well and you get a free extra pilot which is nice.
Ancestral Mech: You get a free light 'mech based on your origin location. This drops on the third day. Note that with your Heavy Metal crate, this will put you over your starting 'mech bay capacity, so be aware of that when making your choice. Also, don't select this option with the Deep Periphery ancestry if you're hoping for an effective 'mech.
Radio Crowd: Another set of pilots, this time unique voice actors. See if you can recognise them! This may not seem like the best option, but when you're getting stomped, a worried whine from a creaky-voiced old man is hilariously uplifting.
Original Adventurers: You get the original pilots you started with in the vanilla campaign, now with upgraded portraits! If you lose Dekker this time, it's on you (it's always been on you).
Tank Crew: Adds a set of ronin to your barracks capable of piloting tanks. It's a great idea to pick this if you want to focus on vehicles early.

Your portrait options are expanded, as are your voice options. Have fun.

First Days

Note: if this is your first time loading, with the Skirmish mech bay workaround, your game will likely chug at this point. This is normal. Tough it out or save and exit if you like.

The first thing that is going to happen is that you're going to get a big ol' crate of free spare parts. You might need them. You might end up selling them. Shut up and take them. At this point, open up your mech bay and take a look at what mechs you got on generation. This might influence what skills you select on your commander. For example, if you have a 'mech with an active probe, you might forego a second pilot with Sensor Lock/Target Prediction.

Which is a nice segue into your next task: evaluating your pilots. As stated, you should aim to have two pilots with Sensor Lock or Target Prediction. These will be critical to your early game because your accuracy is going to be terrible. Sensor locks still stack (with each other and Target Prediction), but Target Prediction does not stack with itself. Two sensor locks are fine, two target predictions aren't great, though you can roll them sequentially for an ongoing buff. If you lack two pilots with sensor-type skills, spec your commander into one. This might seem like a waste early on, but later on in the tree Master Tactician still ain't bad and Knife Fighter is fun. Plus you can always just buy the Training Module 2 Argo upgrade in order to unlock the ability to re-spec your pilots.

If you DO have two pilots with sensor-type skills, feel free to go nuts with your commander's skills. Getting to piloting 6 ASAP is advisable because that +1 hit defense is a not insignificant boost to your survivability. Your commander is also the only pilot who can kinda get away with low Guts, but that's going to suck regardless. There's something to be said for running high Gunnery, especially if you have extra Commander XP and you rolled a good Heavy Metal crate, so consider waiting to make your skill/stat choices until you know the full extent of your 'mech list.

Advance time. On the second day, you will receive an invite to BTA Live Fire exercises. If this is your absolute first time through, go through them. If this is your Nth time through having gotten stomped all thorough-like consider going through them.

Following the live exercises, the Heavy Metal crate drops. Yes, it's actually random, and has an extended drop table. If you're seeing repeated drops of the same mech, welcome to BTA! We are all helpless before the baleful eye of RNGesus.

Day three brings your Ancestral 'Mech if you chose one. You're almost ready to kick a 'mech in the crotch!

Now check out out the biome of the system you're in. You can do this by clicking the Argo button on the toolbar on the left of the screen and hovering your mouse over the system box in the bottom right of the screen as seen here: (Mouse-over the box indicated by the arrow. Climate is underlined in red):

Are you on a lunar, desert or Martian world? Get the hell off it. You have enough going on without having to deal with extra heat management. Save that for, like, month 3 or something. Go find a different world - NOT a half skull world: these tend to spawn more vehicles than 'mechs, and initially you will struggle against vehicles. If you do decide to fly off to another world remember to start any refits and engineering before you take off and check the store for any equipment/ammunition you might need. Engineering upgrades should prioritize MechTech points and extra 'mech bays when you first start - once you're more comfortable with career progression feel free to branch out. Some refits to consider: replacing any autocannons with UAC/LBX versions if you got a drop with those in them, stripping large lasers and PPCs off lightly armored 'mechs and replacing them with more armor and smaller lasers and, if you have an SRM boat, buying inferno ammo from the store if it's available.

Actual Advice

General Gameplay

Movement

With permanent evasion being a thing, the meta shifts towards lighter 'mechs that can move. Obviously Bulwark and Cover are still great, but lighter 'mechs are much, much more viable now than they were in vanilla. As a rule, sprint for max evasion pips every turn whilst trying to stay in cover. 8 pips good, 6 pips and cover good, 5 pips and cover... not ideal, but still kinda ok.

Situations where you're confident in killing the last target may require just moving for better positioning and accuracy, but early on, keep those pips up. You'll be safer and learn more.

Sprinting reduces your accuracy on that turn by -2 and jumping by -3. The jump penalty can be moderated by using it to take high ground, which confers a bonus based on how high you are compared to your target (and negatives for being below them). This means that early on, you really need to get your Kenobi on and take that high ground. Take the high ground and bait the enemy towards you. At the very least equalize the heights.

Positioning continues to matter in BTA, with all the same tricks you learned in vanilla, but with a new caveat: obstructed targets get damage reduction to certain parts of their bodies. 'Mechs take 50% less damage to their legs when LOS is obstructed (look veeerrry closely at the spot where your targeting line changes color. See that eye? that means obstructed) and vehicles get a 50% damage reduction to all parts, minus the turret. Quad mechs (yes, BTA has those) take 75% less damage. All of this applies to the opfor as well as yourself and the damage reduction stacks with cover making some targets incredibly resilient, so pay attention.

Shooting

You may notice that chances to hit seem very low to begin with. Especially in the early game, the combination of fast-moving high evasion light mechs and vehicles as enemies combined with the generally low Gunnery skills of your pilots can make hitting targets quite tricky. There are a number of things you can do to give yourself a leg up though:

General Tips:

Always take the high ground whenever possible. For every 20m height you have over the target you gain a +1 to hit bonus and the enemy receives a -1 penalty to hit you so it helps keep you safe as well. Conversely, if you're below your target you'll have a tougher time hitting them. Use those jump jets!
Range matters. Pay attention to the range brackets of your weapons. Shooting at anything further than short range incurs an accuracy penalty: -2/-4/-6 to hit for medium, long and maximum range respectively. Further to that, trying to shoot something within a weapon's minimum range incurs a whopping -8 to hit.
Use weapons that increase your chance to hit: Inner Sphere standard lasers, pulse lasers, Artemis LRM/SRM, Streak SRM, and LBX with cluster ammunition all have either increased base accuracy stats or ignore some evasion. All Support weapons ignore at least 3 evasion and sometimes more. Full details can be found on the weapons page.
Support gear like TAG, Narc, MG Tracer ammo, and C3/C3i/C3M all help by applying bonuses to hit on targets.
Skills like Sensor Lock, Target Prediction and Battlelord are invaluable for the accuracy bonuses they provide. Use them often.
You can leave your Commander in the barracks to provide your pilots with a StratCom bonus. By default this is +1 bonus to accuracy which is what you want early on, but you can change to the increase resolve as well. That said, depending on how much starting XP you gave your Commander in the new game settings they may be your highest Gunnery skill pilot, in which case it might be wise to keep them on the field at least until your other pilots start skilling up.

Dealing With Evasion:

Sensor Lock is your friend. As mentioned elsewhere in this guide you should have at least one pilot with Sensor Lock but preferably two. Strip as much evasion from your target as possible then focus it down with your better-armed 'mechs.
Doing enough stability damage to a 'mech will cause it to become unsteady (or even knock it over if you hit it hard enough). Once a 'mech is unsteady it will lose all its evasion. Use hard-hitting weapons like Autocannons and Thunderbolt missiles to make them unsteady.
Destroying a 'mech's leg with kicks or called shots will automatically knock it down and strip all evasion. Sweep those legs.
Speaking of kicks: successfully kicking a 'mech strips ALL evasion from it and kicking a vehicle strips three evasion. If you can get a kick in without putting your 'mech at too much risk, do it. Not only does it do good damage to the legs of your target, but they'll be easy pickings for the rest of your lance.

A major change to shooting in BTA is the ability to change firing modes and ammo types. Click the ammo to switch between ammo types you have equipped and click the x2 or firing mode to switch between, well, firing modes. Note that weapons with rapid fire modes have jam chances that usually take over at 50% of their max firing rate. Clearing a jam is complicated math based on your Gunnery skill - when low it can feel like forever before your UAC/10 clears, alas.

Speaking of UACs, note that because of refire penalties on autocannons and similar weapons, you take penalties on accuracy when firing autocannons on subsequent turns. This mechanic was present in vanilla, but less accuracy variables, and vanilla's fudging of accuracy made it really easy to ignore, aside from like, AC/20s. Early on in BTA you will likely find it useful to pause between rounds firing autocannons.

Targeting, while nerfed with the changes of precision strike, is still incredibly important in BTA. When you do get a called shot, right click the 'mech and hover over the parts in the top drop-down to identify what gear is where. You'll eventually internalize things like "what 'mechs have XL engines" with enough play but it's useful to find out where the ammo is, so you can target or avoid the fireworks associated with those. That outline also gives you the armor and structure totals for each part, letting you determine how much fire based on your hit percentage to direct at, say, a leg that you want to lop off.

You can re-arrange your firing order in the 'mech bay. This little button here:

You can also rearrange the order in battle by using the up and down arrows found to the left of the weapon names as seen here:

Guns at the top fire first. Never accidentally fire frag ammo into armor again. Marvelous.

Finally, the tooltips will tell you "guns off the table." We cannot emphasize that point strongly enough. If you can kill a thing, make it dead, now. At the very least 1 completed objective lets you withdraw in good faith. You might be doing that a lot.

Melee

God, I love melee. I especially love meleeing Clanners. Love the way they cry when 20 tons of 'mech leg embeds itself into their reactor through their crotch. Some things to remember:

Punches target the upper body, kicks target the legs. This is karate, not Taekwondo. Physical weapons are a mix, some roll like punches, others can hit every component. And charges are rugby played by pacific islanders so just imagine where that hits (everywhere, with serious impact).
Try to only charge when you outweigh your opponent and when you have the Juggernaut skill so you don't end up in a situation where you're at 4 bars of instability because that's a 1 way ticket to Sit The Fuck Down Town, a suburb of Called Shot City.
Guts level 9 grants +1 punch. Brawler grants +1 kick. Yeah, the kick has a higher chance of removing a limb, but punches' roll table includes the head.
Clan 'mechs suffer a massive penalty to hit with melee attacks. There are ways around this. Figure it out for yourself, or just play like a Clanner.

Salvage

NOTE: There are some combinations of parts-to-salvage and damaged parts that give wonky results and sometimes things just go wrong in game. All numbers provided below are based on 5 parts salvage and are verified where possible but please understand it's not an exact science 100% of the time and sometimes Unity just decides you're not allowed to have a good time anymore.

Salvage works much like vanilla, but given all the new shiny 'mechs lying around, you might be tempted to try and focus on getting some that interest you. That's a great idea.

Generally, the same ideas in vanilla apply here - always take max salvage (except in duels). Legging and headshots are best, and prioritize parts over gear. But there are some new elements as well.

The big ones are XL engines. You can blow out a side torso, which destroys the engine but you get a majority of parts. Note: this will not work with Clan XL engines.

In addition to kneecapping and headshotting, you have two more high-salvage options:

Ejecting: basically a self-headshot, a 'mech with all limbs intact will result in max salvage on the 'mech if the pilot ejects. Forcing pilots to panic is a fantastic early game source of new 'mechs.
Engine crit-out: an engine has three crit "wounds." If you manage to crit the engine three times without coring the mech, it leaves max salvage (assuming you didn't blow off any other pieces). Note that sometimes you will see "CRIT X3." These count as 1 crit. Sorry, engine makes the rules, not me.

In cases where there are some extremely high priority pieces of gear on "offer" or where you don't have many salvage picks, you may want to prioritize gear over parts. Instead of trying to save parts, core the 'mech. You get 1 piece of the 'mech and all of its undestroyed gear. If you really want to manipulate your loot pool you can pick all the arms and torsos off a mech to make sure it eventually only gives you 1 part and 0 gear.

You can construct 'mechs out of related variants - HBK-4G, HBK-4J, and HBK-4N can all be used to build a Hunchback. The one built is the one you had the majority of the parts for. Note that some 'mechs may "appear" the same as others, but are in different weight classes - Centurian-9s and -10s are good examples. These cannot be used to build each other. A good way of telling what can be mixed is by checking the corresponding 'mech page on the wiki. All variants that can be mixed and matched will be on the same page.

Dealing with Vehicles

Vehicles, in general, have elevated armor and reduced structure compared to 'mechs. The lighter ones also move ridiculously quickly and the heavier assault vehicles mount an absolutely withering amount of firepower.

There are several options available to you for dealing with them, however:

Vehicles take 1.5x damage from melee. This, plus your expanded melee options, like double kicks from the Guts tree and the sheer damage output from charging, makes for effective removal of medium and lighter vehicles.
Vehicles don't have a heat bar like 'mechs. They take that heat damage as direct damage, doubled. Inferno SRMs, mortars and plasma weaponry as well as traditional flamers work really well here, as is trapping them in burning forests so they take damage when starting in tile that's on fire.
Thunder, aka FASCAM ammo is good for trapping vehicles as they will try to avoid the mines it lays. Also does reasonable damage if they don't avoid it.
Vehicle line of sight is limited compared to 'mechs - their height matters. This makes taking down assault vehicles potentially easier because of their slow speed. Stick a rock between them and your lance and use sensor locks and indirect fire to ruin their day, even when they show up in 1.5 skull mission.
Piercing weapons are an option, but require you to boat them large numbers in order to produce a good effect.
They only have one structure "location" so while chewing through the tough exterior is more difficult per-location, they a) have fewer locations and b) *only have one structure location*. This makes them far more susceptible to focus fire than mechs - less chance of scatter across a wide number of attackers. There's an element of visuals here because you don't get the satisfaction of getting limbs blown off, that visual feedback of progress.

In general though, the big problem people face with vehicles is prioritization. That little Packrat is absolutely irritating and when its Large Laser hits it can hurt, but it is likely a lower priority than the slower vehicles, even a junky Hunter. So long as you're properly protecting your facings, save your shots until you can safely mass enough fire to land hits through its 8 evasion + defense bonuses. A Mortar carrier with Mortar 8s though? Kill that thing now. Carriers, except for some laser carriers still, uh, carry the full weight of their threat over from vanilla.

There's an upside to vehicles as well. They are gear piñatas. Specialty ammo types, artillery pieces and even some Angel ECM can all tumble out of them like candy if you hit them right.

Miscellaneous Tips I Couldn't Fit Elsewhere

New Mission Types

Aside from new flashpoint chains that I won't spoil for you other than pointing you in the right direction, there are 2 new mission types: Blackout and Duels. Here's some info on the new features:

Extended Flashpoint: Play the flashpoint "Yang Virtanen's Big Score" and wait.
New Flashpoint Chain: Make friends with the pirates. Note that while pirate contracts have been opened up to more unsavory areas than the vanilla map, this chain will make you travel within the Inner Sphere.
Blackout: A highly variable mission that starts with you getting the shit kicked out of you. Or ambushing the ambushers! It's craAaAaAzy variable! Watch out for that first objective - you might want to crowd it.
Duels: A variety of duels and ambushes can occur. Please note that the enemy cheats and so should you. Screw those guys.
Prototype: Bloodydoves rebalanced the final mission. Everybody say "Thank You, Bloodydoves."

IT'S TIME FOR AMID'S OPINIONS

/brooklynNineNineDotGif

Yes, sticking ammo in the legs is still valid. It gets LESS valid once C.A.S.E. is an option. Losing a leg is a death sentence in BTA (Ok Google, how far to Sit The Fuck Down Town?), whereas losing a torso just sucks.
Don't keep more than 2 engine cores of a type. They're worth good money when sold and drop frequently.
It's worth having 2 scouts, 1 dedicated melee and then whatever else you like. Melee is just too good at dealing with speedybois and map control never went out of vogue.

Final Note

And don't forget, if you ever have any questions feel free to pop in to the BTA Discord server. The BTA team and the player community are always happy to offer tips and suggestions to help ease you through the difficulty curve.