Similarly to the first installment of the franchise, the XCOM 2 allows the commander to build and develop his own base, to increase the effectiveness of his soldiers and be able to keep up with the aliens' most advanced units. There's a lot less space for construction now, but it doesn't mean that you will have to give up on some facilities - if you want to, you can construct all of them and you shouldn't run out of space.
There's a total of 10 facilities in the game:
- Proving Ground
- Guerilla Tactics School
- Power Relay
- Resistance Comms
- Psi Lab
- Advanced Warfare Center
- Shadow Chamber
- Defense Matrix
All of the above were thoroughly described in the following chapters.
A thing worth mentioning is the fact that the time required to build a facility, that can be seen in the tables, can be shortened with the help of an engineer - you just have to place him on the construction site (about which the player will be informed once the construction starts), which will significantly decrease the time needed to finish the job.
There are other facilities on the ship as well (such as the Bridge, Living Quarters, or Armory), but those are there from the beginning and you can't upgrade them, nor you can demolish them to use the space for something else.
Information about the order in which you should construct various facilities (as well as their numbers) can be found in the "Base development" section.