there are 2 questions you need to answer

the first is "does the car you are planning to the the 24V lump into already have air con?"

if the anwer to this is no then you can't fit air con to that car without serious remodicitation of the bulkhead as the air con bit that sits there is significantly bigger than just the heater motor

the second question is "you already have air con so you need to splice the air con loom from the car you have into the loom that you want to build into it"

this is a bit more difficult BUT at the same time, easier
you already have the loom for the air con from one car, you just follow it along with the loo for he other car (the 24V) and use the same places to intersect it

this is a LOT easier than it sounds though but we are talking of only 4 wires tops really
you already have the idle booster so all you need to find is where it links into the 24V loom and where it links into the original loom and you have one sorted
the second is where the cut out is for cranking/wot
again, find the source wires for this on the original loom and on the 24V and sorted