arriving in PEK on Air canada, need to catch a flight 3hours later with eastern airlines. Tips?

Well, Air Canada is located in T3, and China Eastern is located in T2. But don’t worry, you can take the free shuttle bus from T3 to T2 very easily.

Your transit process would be like this: Inspection & Quarantine, Exit and Entry Frontier Inspection – Baggage Claim – Customs Inspection – Going through Transfer Formalities – Security Check – Waiting & Boarding.
Anyway, 3 hours would be enough for you. Take it easy.

Wish you have a enjoyable journey!