Very, very simple! You mention stock location? That's where I put mine. I took the stock wires from the stock horn, hooked them to the coil on my relay, ran a single 10 ga. wire with a 20 amp inline fuse back to the battery for power to the relay, and a 10 ga. wire from the relay to the horn. Then took another #10 wire, to a ground, for the ground to the horn. MAKE SURE you connect + to +, and - to - on the horn - a little hard to see on the casing or the horn, and not obvious.
I had to make a different bar, than the stock stacked set - it wasn't strong enough. So grabbed a piece of stainless, and polished it. Also had to make an aluminum stand-off, which I polished also.
I'd use at least a 20 am relay, but I had a 30, and that's great - the horn draws 18, if I recall. The stock wires are NOT big enough to handle the current draw. I hid the relay up by the horn, under the frame cover.
Here's a pic - better would be black wire, but red was in my box:
