If this is what I think, you just have to load the "Demo" DB to test it out.
Think the thread gave few more details on using the included test cart samples, will try to do a deeper search later on.

Do you know what the previous cart was?
Sorry, I don't have any details about his previous cart or host. There were a lot of broken/missing links when I first looked at the site, that I think related to the checkout process.

Best Regards

Keith