Geez! A 40GB hard drive and half a gig of RAM is standard?! Maybe that's sub-par for high-end business color laser printers but I'm impressed. I like how it has a USB port too, perfect peripheral for a single PC.
More than likely, since it's designed to be user upgradeable, you just pop open a cover and stick the module in just like a regular PC. At best you might need to pull off a metal cover, like with Lexmark lasers. These days they're the same type of slot with the retention clips as a regular PC module, though of course they're probably designed to only accept the Xerox proprietary modules.