Let me start by saying that I appreciate any help I can get here. I'm very new to motorcycle maintenance, though I've been riding for over 20 years. This is my first older bike, and the PO has left quite a few things undone, or poorly done. I won't get into a bunch of those details, but my primary task right now is to get a working horn on this bike so it will pass inspection and I can get it licensed.
As I purchased the bike there was no horn. The PO handed me an old horn but has no wires and I'm unclear where to tie it in. He pointed to this hookup I'm showing in the picture as to where the horn would tie in, but I don't believe that's correct based on wiring diagrams I've seen.