Top and back centers off
Step 1 / 4
U': Two layers around the top corner: turns counterclockwise (looking at the top corner)
The right center is right. The top center and the back corner's center are off.
U' fixes the top center first. Rw' brings the back center to the top, the top center to the right and the right center to the back. U turns the back center, then Rw brings all three back.
Step 1 of 4: U'. Two layers around the top corner: turns counterclockwise (looking at the top corner)