The university enrolment fee covers your semester ticket, which allows you to use public transportation in Berlin. The ticket applies to S-Bahn, U-Bahn, Bus, Tram and even some regional train and Ferry trips. Timetables and routes can be found on the BVG Website.
For mobile phones, we recommend Öffi (Android) and FahrInfo (iOS) for Berlin public transport.
Exploring Berlin by bicycle is a great alternative to public transportation and an excellent way to get to know the city. As the university is quite spread out, you may wish to get a bicycle to cover the distances between the administration offices, the cafeteria, the GEAS and various libraries on campus.