If you are flying to a Canadian destination or an international destination, you have to go to Departures security screening checkpoint “A”
If you are flying to a U.S. destination, you have to go to Departures security screening checkpoint “C”.
So that the screening process goes as smoothly as possible, make sure you do not have any prohibited items, as determined by CATSA, on your person or in your luggage. You will also save time by either not wearing any metallic objects, or placing such objects in your carry-on luggage before lining up.