Now, in the top photo, I am giving the inside of the cable jacks a good snip (not a twist or a pry). Once you get some clearance into the inside of the jack, stop. You only need to remove enough plastic so you can see the strip of metal, and trace the + and - connections.

If you're unsure of which wires go where, gently insert an actual cable into the jack, and watch where the tip and sleeve connect. Tip = positive or hot, sleeve = ground.

If you look at some of the photos later in the tutorial, you'll see how I wired the jacks. Do it however you want, as long as you keep In and Out positives separate. Grounds should join each other. Although this step seems easy, it's wise to double-check your connections with a meter.

Now disassemble the switch (the blue plastic square in the 1st photo). With the switch taken apart, you'll see that there are two main solder connections on the bottom (see 2nd photo). The pencil in the photo is pointing to them. In this case, just solder one wire each directly to those. I ran these wires to a momentary pushbutton switch. But a regular DPDT will work, if you get used to the unorthodox movement of the switch (you'd have to switch it On and then Off again, but it would work).