Refer to the picture taken previously to know which solder points to connect your wires to.

Choose a sound driver and put it in front of you on your work surface.

Hold onto your soldering iron with one hand and the wire with the other. Bring the soldering iron tip to touch the solder point that is marked with a Sharpie or paint.

Once the solder point liquefies, bring the left cable so that the copper colored wire touches the liquid solder. The copper colored wire will sink into the solder point and some solder will envelop the tip of the wire. Put down your soldering iron and let the solder point cool down to solidify.

Repeat the above step but with the green wire and on the other remaining solder point.

For the right side, repeat the above two steps. The copper colored wire goes to the side marked with sharpie/paint, and the red wire goes to the other solder point.

Ensure you hold the cable at least an inch away from the tip of the wires to not accidentally burn yourself.