Resizing gallery

Can someone please help me with this. I’ve been trying to figure out how to use this gallery:The gallery with thumbnails and multiple galleries (both mx and mx2004 files)V3_with_thumbs zip

When I download the zip file I don’t understand what I need to change in the action script to use my own photos. I also want to use a different size thumbnail. Here’s my files: http://www.heathertom.net/photos.zip

Can anyone help me get started with this gallery and tell me what I need to change on the action script?