Yep, you bring the hot water, the machine does everything else! There is a pressure seal directly in the group head that holds the water in at the end of a shot. You can preheat just by pumping water into a cup for a couple seconds, which is around the same as a purge cycle on a traditional espresso machine. The fluid path is kept as small and as insulated as possible to avoid thermal losses or unnecessary water being held in the machine.
I added a pre-release version of the manual to the warranty page! Please excuse any minor errors.
I definitely agree that there needs to be a simple clean 30 second video of the full workflow with every part visible - I will work on that ASAP.