Normally when you have a template it comes in a PSD form and it already has all the layers and shadows. Most of the layers will be named. (insert photo here)
You drag your paper or photo into the template above the layer you want it applied to. Then you group with previous. Tell us what software you are using and someone can give you the correct way to do that.
I am using pse 5. Yes sort of makes sense will have to try it. Seemed that when I opened it into pse 5 that is was there but not in layers. Maybe I just didn't know what to look for.