Step 13: Prepare the Battery Cover
Do this outside because it creates lots of tiny plastic particles that float in the air and probably isn't the best thing for your lungs.
After that is over, screw the battery cover back on the DS. The four wires should fit nicely through the groove you created. Put a piece of electrical tape over it to hold the wires in place. Put a piece of tape over one of the wires from the battery to keep it from shorting.
It is also a good Idea to turn on the DS at this point in time. If it doesn't turn on, you're doing good! If it does turn on, you probably forgot to cover the battery terminals. Do that now if you have'nt.