Thank you, but the answer to my question is not in the video. I can start the emulator and the games, but I cannot enter the quick menu of Retroarch once it started using F1. It seems like my keyboard is shut off. ESC doesnt work either. All my other cores in RetroArch work fine.
edit: I have found a way to enter the menu, by make RetroArch windowed (alt-enter). I can control the menu with my (Xbox One) controller. I have set the buttons of my controller and found the option to switch between mouse and controller and assigned that to F10 on my keyboard. I know that works, because when I use that key I can use the mouse and when I use it again I can't use the mouse. But the controller does nothing.
edit 2: the problems seem to be the selection of the 'Retropad'. When I choose 'Joystick' or CD32 it works. Strange, as in all other cores the retropad works straightaway.