@Luca1 you do need to go into retropie menu and go into run command and disable joystick so you would need a keyboard to change video mode and emulator. You MUST do that before this next step. To remove the retropie menu you need to go to /opt/retropie/configs/all/emulationstation/gamelists/ and find the folder "retropie" and put something like an exclamation point in it. So it will look something like "!retropie" now they cant get into anything they shouldnt. Just remember once you set it into kids mode you can get it back to normal mode with the konami code by pressing up, up, down, down, left, right, left, right b, a, start.