[leegrady]

Ah, fuel evaporation. I just love the smell of them motors. The EPA guy didn't want the vapors stored in the charcoal canister to be burned until the engine is at operating temp. So the vacuum line goes to a coolant temp switch screwed into the intake manifold, it wont let vacuum through until it reaches a set temp. From Manifold absolute pressure (not ported) vacuum runs to the temp switch then to the top smaller vacuum fittings on the canister. This will open the valve to purge the vapors.
Vapor go in at the "bowl" and "fuel tank" fittings, and go out to be burned from the "PCV". This is a basic description. Vacuum configurations will vary from year, make, model, but this is basically how it works. Check manufacture spec' sheets, (factory manuals are the best source).
EGR valves have similar configurations, but ported vacuum not MAP. The EGR valve cannot operate at idle. The dilution of air/fuel charge will make the engine stall at idle. EGR valves cool combustion temps to stop the production of NOx which produces tropospheric ozone, better known as "smog". But I digress.
(Note too some charcoal canisters have a round filter located on the bottom that needs to be replaced upon normal service schedules.)
Good luck, and watch for leaks.