Docker - Install an application that requires a screen

Good afternoon,
I want to create a docker under Debian that installs PiVPN. PIVPN


starts a graphical setup, therefore a VNC server should be used. Now the installation with this docker file fails because you have to specify the keyboard layout. How do I make it now that the automatic selection is done and the output via VNC. I am a beginner and would appreciate help :slight_smile: