The Main Building is where most of the action takes place. There are offices, classrooms, and common areas on the first two floors. The third floor is where the under-18 dorms are, followed by a fourth floor which is housing for some of the staff and X-Men.
Cerebro, the medical and science labs, Danger Room, hangar, etc are also under the main building, with tunnels connecting to other areas. Clearance is required to access certain parts of the sub-basement, so please make sure that your character is allowed to be somewhere before posting them there! Sub-Basement Click to embiggen.
Office Assignments Medical Office - Science Office (in med lab area) Tech Office (in hangar area)
Basement
Ground Floor
Second Floor
Office Assignments Office A - Erik Lehnsherr Office B - Office C - Office D - Kate Pryde