Bottom line, the difference is in the name (took me a while to catch on, too):
RW uses water, but no rinse is needs to clean the product off the car. You'll need a bucket, several gallons of water, a couple ounces of RW, and several DST (preferred). Then, wipe the car down with the towels. RW is used for dirtier cars...but not caked on. As mentioned above, you can dilute RW to make a waterless wash-like solution, at a much more economical price point.
WW dos not use water. All you need is the bottle of product and a couple WW towels, and away you go. WW worked well for light dust, finger prints, etc. This stuff smells incredible, by the way.
Be sure to watch the videos on the product pages via Adam's website, as well as their video link, for more details.