Place the included tracing paper over your photo, and trace the printed circle with a ballpoint pen, pressing hard. This will make a groove in your photo's paper without marking it. Cut along the groove with small sharp scissors, and place the cut out photo in the locket. Run a toothpick along the edges to push them inside the hidden groove in the locket. Glue should not be necessary if the photo is precisely cut, but you can add a droplet for extra security.