Well, there are 4 major components - the condensor in front of the radiator; the compressor which mounts on the engine with brackets; the evaporater (aka "suitcase) is sandwiched between the firewall, and the balance are the hoses and misc components that attach to these.
The only one that really matters to go first would be the evaporater - ideally that is installed before the sheet metal is installed. Thereafter, the rest of the components can be installed in any sequence, assuming your are putting your whole car together. The hoses will need to go on last to connect the system.
Regarding proper operation - learning from experience here - make sure the heater core has been leak checked or just replace it. I didn't do that and it starting leaking 6 months after I completed the restoration. It is a major, major pain to replace!