It is pretty straight forward actually, the toughest part is routing the wiring neatly so it does not get abraded (away from sharp edges), and splicing the 'trigger' wire.
For what you want to do, it should be easy.
- Splice a wire from the highbeam circuit to the coil terminal ( terminal 86 on a standard aux lamp relay ) on the Relay - though, I would recommend a dash switch anyway
- Run a ground for the trigger circuit ( term 85 )
- run a wire from the battery through an inline fuse to the power circuit of the relay ( term 30 )
- run wire from the relay ( term 87 ) to the aux lights
- ground the lights to the truck frame
Keep in mind, the terminals I specified here are the normal ones, verify they are correct for the actual relay you get from the store
I learned this one the hard way, I got a relay where the coil terminals and the power terminals were reversed and I fried the relay and burned up the trigger ground wire almost instantly - also learned the value of a fuse in the proper place that day...
Oh, and go with decent size wire, I would suggest no less than 14 Ga. And heat shrink all connections to keep them water tight, plus solder where you can, instead of crimp connections - will last longer.