My dad fell over the kids. The computer taps "+","-" and then enter. These three buttons are placed on a normal key next to each other. We take a plastic card, run three buttons (there is a thread needed) and the computer is turned on. For children, the explanation is that the computer is now turned on only by this card, which is hidden, so that without the parents you can't turn it on. I was surprised, I believed, we have only turned on a card for a week.