We have an online course management system called "Campusmanagement". You can use it with your ZEDAT-Account. In the "Campusmanagement" you apply for the courses. If you did pass a module you will see the given mark also in the "Campusmanagement". There may be additional entries like "regular attendance" and/or "successful attendance".
The apply-period is starting with the semester, that is 1st of April for the summer semester and 1st of October for the winter semester. It ends 3 weeks after starting of classes. Actual details you will find on the HOME-page of the "Campusmanagement". You may withdraw from your application up to two weeks prior to the exam. After that deadline you will get the mark "not passed" because of an "unauthorised absence". If you fall ill this would be an "authorised absence" - if you prove the reason (sick certificate).
If you have problems with the campus management you should immediately contact the examinations office.