Use a sharp knife to remove the insulation of the wires. Do it carefully so as to not cut through the wires.

Here are the three wires in the middle of the cable: red, blue, and gold. Now it is time to figure out which wire goes where.

The three wires DO NOT have any insulation that can be removed. The colors are actually the insulation and it will melt during the soldering process. Or one can use a lighter and melt the color insulation.

Remove the battery by sliding the cover to the right.