Horn Button Install - 1958 Chevy Truck

[TFagan]

I need instructions and/or tips on how to install the horn button assy on my 1958 Chevy Truck. I have purchased some aftermarket replacement parts (picture attached). I bought a new steering wheel, contact plate, contact bushing and cap. I installed the contact bushing into the steering wheel - installed the steering wheel and tightened the steering wheel nut - removed the nut and placed the contact plate with the fingures pointed outward for the cap - re-installed the nut - placed cap on the fingers of the contact plate - hooked up the battery - horn honked and would not quit - WHAT AM I MISSING - something very simple I'm sure.

thanks in advance
Tom