going back home,my flight from toronto-bejing. Then to manila. how to proceed my next flight?

Hve you had the ticket for next flight? Do you mean the flight transfer procedure? As it is the transit of 'International to international', you need refer to the steps:
1. Transfer Procedures: If you have the connecting flight boarding pass, you need to verify the boarding gate of your fight via the fight display screen, and then follow the guiding signs for the transfer circuit to head for right boarding gate. If not, you need to go to the Transfer Counter at 3rd floor for handling boarding procedures according to the direction signs.

2. Border Inspection: go through immigration
3. Security Check
4. Custom Inspection
5. Waiting & Boarding
I have to remind you that if your airlines for the next flight is at the different terminal, you can take the free interval shuttle bus to reach the certain terminal from the one you arrive at.