Strip all the wires out from both cables using a wire stripper. You'll need about three quarters of an inch of exposed copper wire.

If you don't have a wire stripper, you can strip the wires the same way as you exposed these wires. Gently cut the outer insulation, then pull off the insulation.

When stripping wires, do not cut or damage the copper wires. If you do damage the wire, cut off the damaged portion and try again.