Ballast and the light units should be pretty straightforward plug-and play out of the box.
The issue is safety connecting the mess to the truck.
The OTRATTW switch is a nice unit and wiring is pretty straightforward.
Pins 6 and 7 both go to chassis ground. One (7) is the ground for the background illumination, and the other (6) is for the indicator light.
Pin 8 is the supply for the background illumination. You CAN tap that into the dash wiring, but it's a bit of a PITA and if you never dim your instrument dimmer, you can just wire it straight to a switched power source.
Okay... Assuming that you are not wanting to run the lights any time and want them to shut off with the ignition (safest way to go, wired hot 24/7 you WILL eventually come out in the morning to a dead battery).
You need to find a switched hot on the underdash fuse box. The radio and ciggy lighter are common sources.
Remove the factory fuse, and replace it with an Add-A-Circuit.
Before installing, turn the key on, and using a voltmeter or non-battery powered test light, connect the black to a good chassis connection and using the red, check both sides of there the fuse came out. One will have power, one will not.
Insert the original fuse into the terminals on the Add-a-circuit closest to the legs, and insert it into the fuse block with the pigtail wire OPPOSITE where you probed the power source.
You should now have power going to your radio or cig lighter.
Install a 5a fuse in the other space on the Add-a-circuit.
Run one of your 18ga wires from the pigtail to terminal #2 on the switch. You can also jumper it to terminal 8. This will have the switch illumination on any time the key is on, but it is the simplest way to do it.
Now, run your 18ga wire from pin 3 on the switch out the firewall and to pin 85 of a regular "cube" fog light relay.
Connect pin 86 to ground.
Turn the ignition on and have someone operate the switch while you rest your hand on the relay and listen to it. You should hear it open and close the contacts as they flip the switch.
Run pin 87 on the relay to the hot supply wire of your light ballasts. You're going to want to use something heavier than 18ga for this. I'd go with 12.
Now going the other way, run pin 30 on the relay to an inline fuse. This fuse is going to protect the wiring going to the ballasts, so it (and the wire) need to be large enough to supply them. 12ga wire can handle 23 amps enclosed, so I would run a 20a fuse. That can supply 240 watts peak and 192 watts continuous... I would imagine that your driving lights are 55 watts each, so with 2 of them you have plenty of overhead for the power spike at startup.
The fuse needs to be connected to a solid power source that is hot 24/7. Directly to the battery is a good place, but most underhood power blocks have screw terminals accessible where the battery cable attaches and you can usually find a matching nut and simply attach the wire there using a ring lug.
That should do the job.