Beijing Airport Inter-Terminal Transit Route Confusion

Arriving at T2, to meet someone arriving at T3. The bus route does not show a round trip. The information shows two routes and they are not joined together. Should I get on the bus at Gate 11 of T2 and wait for it to stop at arriving floor of T3? To get on the bus, do I have to go to Gate 7 of T2? I believe the departure floor isn't the same floor as the arrival floor and neither is the first floor . Actually, it should be shown as a round route, that can eliminate any confusion. Here is the info:

Place to Get on Free Airport Shuttle Bus
Terminal 1: Outside of No. 7 gate on the first floor
Terminal 2: Outside of No. 7 gate on the first floor
Terminal 3: No. 5 gate on the arrival floor
Travel Route for Free Airport Shuttle Bus
1. Terminal 3 (No. 5 gate on the first floor) →Terminal 2 (departure floor) →Terminal 1 (departure floor)
2. Terminal 2 (No. 11 gate on the arrival floor) →Terminal 1 (No. 7 gate on the arrival floor) →Terminal 3 (departure floor)