Do I have to decide on a supervisor prior to my application to the DPBR?
Yes, you should definitely have discussed your PhD project with a main supervisor and ideally two further supervisors. They all need to agree on supervising your work as part of the Supervisory Team (Betreuungsteam) and confirm their consent in written form as part of the Supervisory Agreement (Betreuungsvereinbarung). This document is a required part of your application.