Help with inserting picture into a template

Hi All,
I have a picture that I made in paint shop pro 8. I am trying to put it on a pre designed template from

http://www.vistaprint.com

to make large magnets with my own picture. Vista Print has these guides for making the pic.

Full Bleed Size (starting document size)
5.59" x 4.33"
142mm x 110mm
1677 x 1300 pixels
* Finished artwork should use the full bleed dimensions for best results.
Document Trim Size (final size after being cut)
5.47" x 4.21"
139mm x 107mm
1642 x 1264 pixels
* Please be sure to keep all text within the safe margin.
Resolution
300 DPI

I downloaded the template and opened it in Adobe photoshop CS3. I just bought the Adobe photoshop. I would like to know if there is a tutorial for this or if someone can guide me through it for the first time. I am a new new newbi.

I have the template and now don't know what to do with it.

Thanks for any help you might have.