Larry -
I had a difficult time remembering where or finding the horn button on the few cars that I have driven that had the button mounted under the dash.
Most parts houses have everything that you need to hook up the horn button in your steering wheel hub. Here are parts at Classic Parts of America ... not recommending CPofA over other suppliers, but they are easy to link to.
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Universal Horn Assembly-High Note>
Horn Relay>
Horn Button Retainer>
Horn Contact Spring & Bushing>
Horn Button-Chevrolet 54-55'54 MPC Horn Contact IllustrationThe '54 - '55 1st horn was mounted "on brackets between radiator core and grill". The low note was the standard horn. High note was extra cost option.
Dale's schematic is good.
Here is the way I hooked up the horn on my 12v '54. Suggest bypassing the ammeter as shown on my diagram because the current draw of the horn may peg the needle.
This is the 1954 factory wiring diagram.Good luck with your new horn.