Are you planning on doing a PhD after finishing your degree? Have you already picked a topic and found a supervisor? Or have you secured a spot in a PhD program and found at least two persons agreeing to be part of the supervising committee? For further information you can contact Prof. Dr. Herrmann.
The next step is applying for admission which you can also do in English. An important part of your application is a synopsis of your research project, including a timetable.