Back · green on the left
Step 1 / 4
U': Two layers around the top corner: turns counterclockwise (looking at the top corner)
The yellow-green edge is at the top back, with green on the left face.
U' brings the edge to the top left with green in front. Then do R U' R'.
Step 1 of 4: U'. Two layers around the top corner: turns counterclockwise (looking at the top corner)