The internet page of the "Foreign Office" [2] provides detailed information on visa guidelines for travel to Germany [3]. You can also find further useful information via the "Welcome Center" of Bonn University [4] and the portal "Euraxess Germany" [5].
On arrival, you must report to the Citizen Centre of Bonn City Council. At the Foreigners' Office, your visa, which is only applicable for entry into the country, will later be replaced by a residence permit.
For residence lasting more than three months, you will in each case require a "residence permit"; EU citizens will receive "freedom of movement certification". Both documents are issued by the "Foreigners Registration Office of Bonn City Council" [6].
For this you require the following documents:
Links:
[1] http://www.mpim-bonn.mpg.de/taxonomy/term/109
[2] http://www.auswaertiges-amt.de/
[3] http://www.auswaertiges-amt.de/EN/EinreiseUndAufenthalt/Visabestimmungen_node.html
[4] http://www3.uni-bonn.de/institutions/welcome-centre
[5] http://www.euraxess.de/portal/Incoming_en.html
[6] http://www.bonn.de/rat_verwaltung_buergerdienste/stadtverwaltung_im_ueberblick/00617/