if you are talking about the line that comes off the round canister on the passenger side of the carb, then that gets hooked to a hardline that has exhaust from the intake manifold run thru it.
there are 2 hard lines that need to be hooked up- one that goes from that nipple to the heat crossover, and one that comes out of the crossover right next to that one that goes to the a nipple on the back of the carb, right under the air cleaner flange.
there is vacuum from inside the carb that pulls the filtered air it gets from the back of the carb thru the heat crossover, which is then heated and pulled thru the choke coil into the carb. this heats up the coil and opens the choke as much as it needs. this is the best choke setup ever devised, and i would definitely try to get it working right. it's way better than a silly electric choke setup.
if you don't have any fittings coming out of the intake for that, you can get an electric choke coil for a newer car or truck and put it into the hot air choke housing. just plug the vacuum nipple on the housing and the fitting on the back of the carb, hook up a switched 12 volt power source to it, and you have an electric choke.
you don't plan sincerity.
you have to make it up on the spot.
wanna hear about 20 years ago when i was too smart to know any better?