You can press ESC (which, I think, is universally the standard command for exiting full screen mode), you can mouse up to the menu bar and click the full screen

You can press ESC (which, I think, is universally the standard command for exiting full screen mode), you can mouse up to the menu bar and click the full screen button or you can use the shortcut that gets you into full screen mode to exit it again. I wouldn’t bother with gestures. I would tell my parents to press ESC. They know that button and they should already be aware that it is often used to exit full screen modes.