Let the kids start by painting a few coats of paint onto the bottle caps similar to the picture below. The line doesn't need to be perfect, so have fun with it! You can coat the entire bottle cap with one color then add a second color over the bottom. or leave the bottle cap unpainted and only paint the bottom. Let your kids pick wich way to do it. Allow these to dry completely before continuing.
Using the opposite end of the paintbrush, let your kids dip the brush end in paint and add dots on their bugs. The more dots you try to make in between dip, the smaller each dot will be. Just let them have fun and experiment with the dots and the placement.Let paint dry completely.
Use glue to add two googly eyes to the front of the bottle caps and a couple of magnets to the back. I had to add two magnets each because of the depth of the bottle cap. Double-check your magnets and test them on the fridge before gluing everything in place. One glued, set aside and allow the glue to dry before use.