This harness is completely prewired.All you need to do is solder your pickups to the switch and ground them to the volume pot.
Product is suitable for harnesses with the following functions: tone knob, volume knob, and switches for upper and lower pickups
for the volume and tone, common for most import guitars. 6 mm knobs will fit these shafts.
It's possible to take the tone knob out of the equation, but you'll have to rewire it, better buy a wiring harness with a single volume pot and switch
If you just remove the 3-way switch and use the volume pot, you can solder a humbucking pickup to the port on the right, then ground the pickup to get a single-knob humbucking pickup