In order to enrol for your courses this upcoming semester, you have to register for courses. You can sign up between 30.03.-14.04. on the LSF under "Lehrveranstaltungen belegen/abmelden".
Please note that this is the current status under the present circumstances.
Possible changes can occur during the next days or weeks, as soon as the LMU made a final decision on the further proceedings regarding the COVID-19 situation and the summer semester. To keep yourself updated you should regularly check the LMU website.
Have a look at the document "How to sign up for courses" before signing up.