SPDT Backup lights switch wiring

I'm trying to add backup lights to my rear bumper with an on-off-on switch so they can come on independently or come on whenever the reverse lights are on. I've been referencing this thread (https://www.tacomaworld.com/threads...ghts-to-switch-and-preexisting-lights.266006/) but still have some questions about wiring the switch.

I'm referencing the diagram that OTRATTW provided with the SPDT switch but am having trouble figuring out how to make their wiring diagram do what I want.

Perhaps someone smarter than I knows how to make the magic happen.

 

you will want to run a wire from pin 2 on the switch to the positive wire (pin 85 or 86)on the relay for the backup lights.

Pin 1 can be wired to the reverse wire.
You can run a jumper wire from pin 1 to pin 8 - this will cause the upper led to light up when in reverse

Pin 3 can be wired to a positive 12-volt input
You can run a jumper wire from pin 3 to pin 10 - this will cause the lower led to light up when selected

What relay harness are you using?

 

Thanks for the feedback! Seems like that should be easy enough to accomplish.

All of the electrical will be going through a Bussman block. The picture just shows the signal harness, I'm still in the process of building the power and ground harness to go with it.