pls explain the flow of T1 domestic arrival then T2 international departure at PVG.

Ken, if you take flight of China Eastern Airline, the transition can be very easy. You will be led to the check-in (R) area to take quarantine, immigration & secutiry check together, and then wait for your flight.
If not, you need to reclaim your luggage after domestic arrival and follow the signposts to international departure hall. Then, take the quarantine, immigration & secutiry check one by one before boarding.