Freie Universität has various campuses. The main building complexes on the Dahlem campus are the so-called Rostlaube and the newer Silberlaube on Habelschwerdter Allee 45, 14195 Berlin. Rost- and Silberlaube are part of one large building complex. There are many other buildings, most of them being located in Dahlem or other districts in the southern part of Berlin such as Lankwitz.
Site maps of various locations can be found here.
You can reach the Dahlem campus of Freie Universität with the following public transportation:
General information about public transportation in Berlin can be found here.