In the Commented Course Catalog you’ll find all relevant information about the courses in mathematics:
Commented Course Catalog: All courses
If you are interested in participating in a seminar, please be aware that in most of the seminars the talks are given by the participants. Many of the talks are distributed at the end of the preceding semester, e.g. end of July for the winter term. It is thus recommended to contact the organizer of the seminar as soon as possible, preferably towards the end of the preceding semester, but no later than two weeks before the beginning of the semester.
Furthermore it is possible to conduct an Independent study project, see Module Catalog ("Modulkatalog bei Studienbeginn ab WS 2018/19", page 125-126). It is required to contact a lecturer.
General information for international students, e.g. about accommodation, formalities, life in Regensburg is offered by the International Office (to be found here).