When I wired lights on my Tundra they came with a nice wiring harness that included the switch and relay circuit. You just plug the wires from the lights into the harness, screw the relay to the firewall somewhere, put red wire on positive battery terminal, black wire on negative battery terminal, properly sized fuse that is built in to the red wire, run the switch wires through the firewall to under the dash, drill the proper size hole in the dash to mount the switch, wire up the switch with the wires from the harness that came with the lights. If you buy lights without the harness, you could always go to an AutoZone or similar store and buy the generic light harness.