So, wiring the switch/relay/lights is one thing, but the switch you posted up is only the actuator (cover piece).
That looks like a Contura V series actuator, Which will mount to a V series body (the actual switch).
These switch bodies have more possible configurations than I can name off the top of my head.
That being said, we need to know which switch body you're going to use, in order to tell you how to properly wire it.
Carling contura-v switches will generally have 8 or 10 pins on the back. For the most simple switch (SPST, on/off, no light), you'll only use two of those pins. As the switches get more intricate, you need more pins.
The switch that came with the Rigids is an SPST lighted switch.
Have you ever used www.circuitlab.com ?
This might help you show him how you wired yours. (it's free)
You may want to include the part number for the switch body so he knows which one to buy.