How do I create a wireframe template in Microsoft Visio 2007?

My manager wants me to create a wireframe using screenshots of a current website design to document the current functionality of the site. I need to do this using Microsoft Visio 2007, however, I have not used it in a while.

I need to know what is the best way to do this in Visio 2007...I do not have 2010 version.
Does anyone have a sample or a link that would show me how the best way to do it in visio would be? I have the screen shots, I just need to add numbers and then a column to the right with an explanation about the section that is associated with the number.

Thanks so much. If I could get an answer as soon as possible it would be greatly appreciated.