First you want to be sure you get the right type. Some are designed for separate turn signals and stop lights and some are designed for integrated stop/ turn lamps like your car originally had. WHY are you doing this instead of "fixing what it had?"
They should come with destructions.
The inputs are:
hazard / 4 way flasher , which may be built in
Turn signal flasher
Stop lamp switch if the switch is built to handle that
Outputs are left front turn, and right front turn
Left rear turn (and stop)
Right rear turn (and stop)
Better to just swallow hard at the price of parts that haven't been made in many decades, buy a new factory switch assembly, and install that. It will be a whole lot less hassle, with a better result, and it will certainly look better than a schlock thrown-on aftermarket switch hanging off the side of the steering column.
I have a good used one for $75 shipped. Drove car, worked fine but is not new. Rare that these go bad. More common is the pot metal holder that the signal switch screws to breaks and the signal lever seeming flops around. I'd pull the steering wheel to confirm you actually need the switch or the pot metal holder. They can wear out of course but in driving these cars for decades I've yet to see a bad switch and have suffered two broken switch holders.