Time of Arrival
Students are advised to arrive in time for the beginning of a semester, that is October 1st for the winter semester and April 1st for the summer semester. Lectures usually start in the second week of respective months, but the introduction seminars for your degree courses take place in the days before the lectures start. You also should consider that the formalities at university and as well with the local authorities take some time which you best deal with before lectures start.
For the exact dates have a look at the academic calendar.
Please go to the orientation events at the beginning of each semester. There you'll get a lot of useful information on study program, degree courses, lectures, examination etc.