Thank you very much. Meanwhile I could find also a helpful video here: https://www.youtube.com/watch?v=SrPuHIt8DX0
I understood, that it is necessary to call the right frequency on atc and that you have to do the things in the right order AND always read back transmissions, right? But now I have this:
1. Positioned the plane right on the beginning of the runway
2. File a flight plan from EDDL to EDDF
3. Request Clearence from ATC
4. Received answer "a gate hold is in effectice for a runway change. Please stand by." (Screenshot)
5. Readback Transmission "We'll sit tight - C-FXCK"
And than.....nothing...... No new command, no clearance, no squak.... any idea? What do I have to do next? And is it possible to start the process on the runway, without taxiing?