1) Under the LBCs tab, select Force from the Loads group.
2) For Name enter 8 lb.
3) Click in the Entities text box and select the node at the far right corner as shown.
4) For Magnitude enter 8.
5) The direction of the force is in the negative z-direction. Enter -1 in Direction-Z text box.
6) Click OK.
7) Turn On Detailed Rendering.