Both universities involved in the MA Global History offer help and advice for foreign students coming to study at either Freie Universität or Humboldt Universität. The Humboldt Universität provides new arrivals with a very detailed and highly recommendable guide addressing the most frequent questions and problems concerning international students which you can find here. Although the correspondent guide by the FU is not quite as extensive it can nevertheless prove quite useful as well. It can be found here.
Both universities also operate clubs for international students:
The International Club "Orbis Humboldtianus" (Humboldt Universität)
International Club (Freie Universität)
ISFU - International students at FU (Freie Universität)