Use sand paper or nail file to scuff up areas on plastic shield where glue will be applied. Scuff entire square where elastic band will go and rectangle where foam will be placed.
Make sure your glue gun is on HIGH. Some glue guns do not get very hot, in this case the glue may be too cool by the time you press that final end of elastic band to the plastic. Apply glue to foam area & press down foam FIRMLY. Next, apply glue to elastic areas & press down elastic band FIRMLY.
Don’t press for a long time - maybe 5 seconds. Just press FIRMLY. Once everything is attached, squeeze elastic band to the glue a little longer to be sure head band is secure.
You may need to use more glue. When pressing elastic band down, glue should spread to outer edge of plastic shield. To protect the template from glue, tape over the squares on template marked “elastic band”.