Your offices will require a certain layout and dedicated rooms to be able to run FAST. In particular a room capable of holding an Open Space styled meeting with the entire Development Tribe - the FAST Meeting.
The Forum is the permanent home of the one FAST artifact - the Release Map. Against this backdrop, the Product Director facilitates the FAST meeting. As mentioned above, this area needs to be large enough to hold the entire development tribe.
Collaboration Areas or Rooms
You need enough collaboration spaces to hold the right amount of teams. (The tribe breaks out into teams/swarms at the end of the FAST meeting.)
There is no reason that you can't use the Forum for a development room.
Ideally, the teams are pair programming. Having rooms set up for pairing and/or mobbing is ideal.
There should be plenty of whiteboards around and at least one in every collaboration area.
Note - This describes ideal. But with creativity, there are always ways to making things work, including remote/distributed.
During the Covid Pandemic, many Open Space events went virtual. Given that the technology exists to make this possible, then there is no reason FAST can not also be facilitated in the same manner.