Insert one end of the retaining clip beneath the edge of its recess cut into the LCD bracket.

Use the edge of a spudger to push the short hook tab on the underside of the other end of the retaining clip into the recess cut into the LCD bracket.

The second picture shows a retaining clip properly installed.

You may find it easier to get the short hook tabs on the underside of each end of the clip to fit down inside their cutout in the LCD bracket by first very slightly bending down the two ends of the clip, but be careful not to bend the clips too much--only a slight bend is needed, and too much force will break them.