Center 4: bring up one piece
Step 1 / 4
Rw': 2 Right layers: turn 90°, front face goes down
Center 3 is done on the bottom. The top is missing its back right spot; the front has a piece at the bottom left.
Use the elevator with F' (not F2) so the piece lands next to its partner. The final U frees the elevator.
Step 1 of 4: Rw'. 2 Right layers: turn 90°, front face goes down