Hi Peter,
First, welcome to Zen Cart.
If you don't already have these tools, I suggest you get them.
1) a good text editor like Notepad++ or Crimson Editor
2) an FTP client like Filezilla
All are free downloads from the net.
Here's what I would do in your situation.
I would connect to the site with the FTP client and download all the Zen Cart files and folders to my local computer. Why? It gives me a backup of the site and allows me to edit files easily which I can then upload to the site to make the changes permanent. If anything happens to the host, I still have a current copy of the store. (backing up the database is another matter, but that can come later)
Once you do that, you'll be able to see the folder/file structure Zen Cart uses and people's suggestions about where to find and edit things will be clearer.
You can use a different background image by adding it to the appropriate places in the stylesheet. I've done that on the Fan Odyssey site in my sig.



Check out my site now, its coming together.
