A/C in AE86

[Red]

The "round thing" is the receiver/drier, and you will need one. The condensor is the smaller radiator in front of the water cooling one.

But there are many parts to need, and multiple versions that are not all compatible. If you can't get ALL the parts from one donor car, at least get the shop manual and parts sheets, so you can make sure of what the complete system needs and which part sets match.

Evaporator, condensor, receiver/drier, compressor, compressor clutch, many hard lines, several rubber lines, some mounts that vary by engine and model and component, a different belt to drive it, the electronics module "AC amplifier" that sits under the glove box with the evaporator, the evaporator drain hose....and then of course the proper gas (R12, R134a doesn't work as well) and a set of tools for the gas, gauges, vacuum suction pump....

This is a major job, probably comparable to a custom engine swap, unless you are familiar with AC systems.