Basically I want the horn on the alfa to only work with the ignition on. The way it is now it works with it off or on. I do have three unused terminals on the ignition switch. How would I go about doing this without hacking the wiring too bad?

The diagram is crazy basic. The battery doesn’t directly go to the fuse panel, it goes through the starter and ignition first.

The diagram is basically saying the fuse for the horn goes straight into the relay which the horn and horn button is directly connected too. AFAIK this is the proper way for it to be hooked up.