I don't think you're misunderstanding the command because there's not much room in the description for misunderstanding. But I'm not sure whether it'll get you unstuck. It moves Manny to the default position in the room so it should, if the default position is actually not on the belt.
As for how to use it, if dev mode is enabled you simply press the Home key on your keyboard. The easiest way to have dev mode enabled is to have installed the game using the Quick & Easy installer.