CMS Made Simple Forums

I have found a shopping cart I would like to use in a cmsms site (http://www.ecommercetemplates.com -generic version). It allows you to add a cart to any page using includes and I figured that should make it fairly easy to integrate, but I have very,very limited php knowledge and don't know how to go about it. Can I add the includes as a user defined tag  and then just use the cart as I would in a normal installation? I have looked through the documentation and understand how to make a udt for simple functions but I'm not sure how it would work with the cart. Or could I use the modulemaker to integrate it?
Any advice would be greatly appreciated as I do not want to buy a shopping cart until I know I can use it.

Thanks
Tim