quick rundown on wiring in a horn...

[FirstGen]

Ok well I've never had a horn on my truck and yesterday some jackleg cut me off royally and I really wished I had one, sooooo I bought a horn and I need some help figuring out what to do to get this thing going.

So far I installed the horn where I remember the horn was factory in these trucks on the driveside radiator support and plugged in the green wire that I found tucked away that I *think* went to the horn? Now my question is does the green wire going to the horn from the fuse block supply positive or negative? I would think positive. I have all new switch and wiring in my colum and I have tried grounding the copper spring loaded button thing and supplying power to it and nothing happens.

Where should I start to look to figure this out? Where is the relay for the horn? Is it the one between the fuse block and the colum?

Thanks!