I arrive on Air China and need to transfer to Air Canada for an international flight at PVG.

First of all, both of your flights are located at T2.
So the correct transfer procedures are the following:
International Arrival Access - Joint Inspection - Quarantine - Immigration - Luggage Claim - International Arrival Hall - Go to 3F for Boarding
You can make full use of the English signs at the airport and finish these procedures step by step.