Ok, the diagram shows norhing grounded at the switch controller unit so here goes. We'll do ur headlight first. The red wire goes to ur battery +. Put a fuse between the battery & switch, as close as practical to the battery. The black will go to one terminal (or wire) on ur headlight. The other terminal or wire on ur headlight goes to ur battery -. Thats it. If u want a tail light it goes in parallel with the headlight, meaning the black wire going from the switch to the headlight must also go to one terminal or wire on ur tail light. The other one goes to the battery - just like the headlight did. Both lights should now work simultaneously off the switch. Ok, vehicle horns usually work by the horn button completing the circuit on the ground, or - side but they'll work either way. To do it the normal way, connect the battery + to one terminal of the horn. Again, put a fuse between the battery & horn, as close as practical to ur battery. The yellow wire would then go to the other terminal of the horn & the brown go to ur battery -. Should u want to do it the other way, put the yellow to battery +, again, use a fuse in this wire, close to ur battery. The brown would go to one terminal on ur horn & the other terminal would go to ur battery -. Thats it, all done. This is assuming no ground connections at the switch, of course. Dont let the Genie out of ur electrical system, use fuses. Cheers