Using these Abaco M3 right - angle clamps is a breeze. First, adjust the jaw to fit the thickness of your bench top. Then, place the slabs you want to secure at a right angle between the jaws of the clamp. Tighten the clamp to hold the slabs firmly in place. When using, make sure the surfaces of the slabs are clean to ensure a good grip. Don't overtighten the clamp as it may damage the slabs. For maintenance, after each use, wipe the clamp with a dry cloth to remove any dust or debris. You can also apply a little light oil to the moving parts to keep them working smoothly. This will help your clamps last a long time and perform at their best.