To insert photos into your Paper and Camera template using Photoshop Elements:
1.) open the template you wish to use into elements (go to file<open<choose your template or double click on your PSD file)
2.) go to file<place and choose your photo. Your photo will be placed into the template
3.) resize your photo to cover your clipping mask (drag the sides of the photos holding down the shift key). You will want your photo to just cover your clipping mask, making sure that none of the clipping mask is showing.
4.) Make sure your photo is directly above your clipping mask layer in your layers palate. Go to layer<create a clipping mask.
5.) your photo is now within your clipping mask and you can move it around and adjust as needed.
to release your photo from your clipping mask go to layer and choose to release the clipping mask.