Move draggable towards the wedge as to make B stand on the wedge. Wait for 2 seconds before tapping the stair in front of him. B's body should bump into the ball and roll it in place.
Time for the autopilot. B can do it. Wait for few seconds and he'll jump into the wedge near the win.
Do the SSS on the 1st ball. Immediately tap the adjacent brick and wait for the rail attached to the motor to push B into the concrete block to access the win.