EMPI 4549 Chrome Emergency Brake Handle Kit - VW Dune Buggy Bug Ghia Trike Baja Beetle

I need help. I bought this hand brake handle for my 71 vw dunebuggy. my buggy was bought used and does not have the floor mounting. is there a digram

What keeps the button/shaft from popping out?

Works for Volkswaguen classic 1957 ?

will these fit a 1971 super beetle?