I'm not entirely sure where to put this so I'm putting it here

I'm doing HotRod Dragweek and a horn is required. Younger me took the horn stuff out of the column and now older me needs it. Stupid then yes, further discussion about it needed, nope. So what all parts am I missing to get the horn working? 1972 Demon in case it matters.

I know I need the horn button for sure.