Hello @saidh
Welcome to our community!
As far as I can see you have to get in contact with the Bundespolizei (police) and tell them that you want to apply for asylum. They will escort you to a camp inside the transit area. You'll have to wait there for your case to be decided.
Applying for asylum in an airport is a special case. If you have further questions about the procedure, feel free to ask.
Best regards,
Thorgen