You can access your Semester Ticket through an online app. The ticket will need to be paid before the start of each semester to allow time for the updates to the transport companies. You can find the instructions to log-in and use your ticket here.
The transportation authorities arrange the Student Semester Ticket based on the solidarity principle. This principle guarantees the lower student price on the basis that all students of the university pay for the ticket. It is therefore a mandatory part of your study fees and cannot be opted out. For more information about the ticket validity, see Semester Ticket/Student Ticket (DST).