Take a pair of black and red wires 43 cm in length

Solder the black wire to the north pole and the red wire to the west of the power connector following the same techniques used for the switches.

Slide the 12v power plug into holder. Note that once side of the holder is slightly larger than the other. It fits better the correct way around.

Thread two M3x10 screws into holder through the two extra holes beside the right-hand motor

Tighten until the plastic meets the wood and the screw is flush with the wood. Do not overtighten or the screw will strip the plastic and fall out.