Copy the graphic by right clicking on it and choosing the 'copy' option.  Paste it on your project by right clicking on the project you are going to put it on and choosing the 'paste as new layer' option.  If it's too big, you can re-size it one of two ways. 

You can click on the deformation tool when it's on the template and you will get an outline around the graphic and you can drag it to a different size now.  Then click on "Effect / Sharpen / Sharpen".

Or before you paste it on the template, click on "Image / Resize". 
Make sure "Percentage of original is checked" and put what you want there.
That means how much of the original you want to keep, not get rid of.
Also, make sure there is a check in "Resize all Layers", and in "Maintain a Aspect Ratio of...". OK the box, then click on "Effect / Sharpen / Sharpen". \

Or, if next to the "Resize Type", you have 'Bicubic Resample' there, no need to sharpen.

This is for filling a template up with an image, so the image is wall to wall inside the template, totally incasing it.

Click the magic wand in the template, using the appropriate tolerance, and feather at zero.  Now copy your graphic, and then choose the "paste into selection" feature.  This will make the graphic fit perfectly into the template.  But keep in mind that it works best for graphics that are big.  If they are too small and you do this, the graphic will be blurry.  You don't want anything looking the least bit blurry or distorted.  After the graphic is in the template, it should look just like it does in it's original state.  If it doesn't, you don't want to use that graphic.  It may be big enough, but it's not the right proportion for that template.  Anything the least bit distorted or blurry is unattractive.