Don’t worry though, you still have plenty of opportunity to do some base-building, though your options are somewhat more limited than in the first game. Here’s what you need to know to get your base set up properly in XCOM 2:
Base Building Basics
A big chunk of the Avenger is taken up by the mainstays of the XCOM project – the command center, the armory, the barracks, engineering, etc. The juicy center of the flying base, however, is filled with what is basically alien junk that can be cleared out so you can build nifty new base facilities.
XCOM: Enemy Within had adjacency bonuses that made planning your base challenging, but XCOM 2 has done away with them – with one major exception. You can now construct a Workshop that allows you to staff adjacent buildings with Gremlins that function as engineers, effectively doubling their efficiency. Obviously, it’s important that you place the Workshop and the surrounding buildings intelligently so you can get the most out of them.
Ideally, your Workshop will go on the second level, with buildings that benefit from being staffed by an engineer above, below, and to either side of it. It should look something like this.
X – Advanced Warfare Center – X Proving Ground – Workshop – Resistance Comms X – Power Relay – X
Before you can even start thinking about that, though, you need to start clearing some alien debris. Your first few engineers should be working around the clock to clear the debris from the first two levels – not only do you need those spots to put buildings in, but you get supplies and other goodies from clearing them out, so it’s absolutely worth it.
You can build some buildings right away – the Guerilla Tactics School doesn’t benefit from an engineer, so you can build it in one of the top corners (this is a good idea anyway, since it happens to be one of the best buildings to have in the early game).
Unfortunately, the game doesn’t always cooperate with you, and you might not be able to pull off the perfect base design. Don’t get behind on resistance contacts or slowing down the Avatar project just because you were trying to build the perfect base. Make the buildings you need when you need them.
Base Construction Order
You should build what you need when you need it, but if the aliens give you the chance to construct your base as you see fit, there is definitely a preferred order to setting up your facilities. Here’s one recommended build order, though you should feel free to make changes as needed.
Guerilla Tactics School > Advanced Warfare Center > Power Relay (built above where your workshop will be) > Workshop > Proving Ground > Resistance Comms
Everything is variable, more or less, except the Power Relay, which you will need to power all of these buildings anyway. After you have this core, you can focus on building story-related projects or expanding things like Resistance Comms and Laboratories. The rest is up to you.
If you’re lucky enough to get a base with a power coil in the center column of the third row, you can try to beeline for it and build your workshop above, which will set you up for power for the better part of the game. But that requires delaying some buildings and may put you in a tough spot. It is efficient, though.
As always, pay attention to the needs of your squad and the situation on the GeoScape. And good luck, commander.