Screw a short wooden batten to the fence posts at the bottom of the fence. The batten should be slightly wider than the gravel board. Screws attach the batten to the fence post more securely than nails do.
Place the gravel board along the base of the fence, between the batten and the fence panel.
Attach the gravel board to the batten, using galvanized metal clips. Clips allow you to make adjustments to the boards, if necessary, without removing the board. Use screws to attach the gravel board to the batten board. If using concrete gravel boards, pre-drill holes through the board with a masonry bit.
Repeat the process on the other side of the gravel board. Continue around the perimeter of the fenced area.