Assuming you have a basic understanding of car electrical systems, wiring a steering wheel horn is not a difficult task. The first thing you need to do is disconnect the negative battery cable to prevent any shorts. Once the battery is disconnected, remove the airbag module from the steering wheel. This will give you access to the wires behind the airbag. There will be two wires, one for the horn and one for the ground. Use your test light or multimeter to find which wire is which by testing for continuity between the two wires and the horns terminals. Once you have found which wire is which, connect them accordingly and then reconnect the negative battery cable. If everything is wired correctly, your horn should now work when you press the button on your steering wheel.