how to proceed an international transfer at T3

You can do as this procedure:
Arrive at the International Arrival Level at 3F of T3-E → proceed with transfer procedures → pass through the Transit Inspection in special passage in the east or west → take special elevator downstairs to International Departure Level at 2F of T3-E → accept Security Inspection in the special passage → go through the customs sample check of hand baggage if necessary → Waiting & Boarding