It's easy to put set-in hooks into fabric with just a pair of pliers. Set-in hooks are best used where there is more than one layer of fabric, like in a waistband, so that the "wrong" side of the hooks always lives between layers of fabric.
1. Mark your fabric where you want the prongs of the hook and bar to push through the fabric.
2. Hold the top overlap of your fabric and push the 4 prongs of the hook from the innermost layer of fabric to the center of the fabric layers so that the prongs end up between the layers of fabric. (If there are two layers, push the prongs through one of them.)
3. Place the square silver backing piece between the layers of fabric and just inside the prongs. Using a small pair of pliers, wrap the prongs around the metal so that the hook is held in place not just by fabric, but also by metal.
4. Hold the underlap of your fabric and push the 2 prongs of the bar side from the outer layer of fabric through to the center.
5. Place the narrow backing piece between the layers of fabric so that the prongs insert through the holes.Using a small pair of pliers, wrap the prongs around the metal so that the hook is held in place not just by fabric, but also by metal.
If you don't get the placement just right the first time, unfold the prongs and set again!