If you have not yet found a flat or room, you can either apply directly to the Wohnungsbaugenossenschaft Ilmenau (WBG) or the housing and Ilmenauer Wohnungs- und Gebäudegesellschaft (IWG) or on the relevant platforms such as wg-gesucht.de or immowelt.de. For the transition, there is a student residence at Stollen in Ilmenau Jugendherberge and the Studierendenwerk offers rooms for Kurzzeitvermietung rooms.
When moving to or relocating to Ilmenau, you must register within two weeks at the residents' registration office. However, a slight delay is usually not too bad. If you do not re-register, in the worst case you will have to pay a fine.