Welcome to FT!

I connected in YVR a few weeks ago. As mentioned, you pick up your luggage at YVR, then follow the signs for connecting AC flights (to the right at the back of the baggage claim area).

If you are landing at the same time as many international arrivals, this connecting area can get crowded, but your luggage should be cleared to Toronto so it should be fine. They were calling for tight connectons and letting them through at security. Worse case, AC would protect you on a later flight and there are many between YVR and YYZ. Have a great trip!