Hi Jess and welcome!! Here are some ways to attatch transparencies to your layouts.
-brads, eyelets, or nailheads.
-acid-free spray glue
- Use your regular adhesive and layer an embellishment on top to hide it.
- Use tacky tape (small pieces in obscure areas of your layout).
- Use vellum tape.
- Sew it onto your layout.
- Staple it.