I can't remember for sure, but I think I was lost at first too. Then I discovered the windows key, and never looked back. I love getting most things done without touching the mouse. Though I did have to install a panel for when I work with more than a few instances of the same program at once (at which point alt tab can sometimes not allow me to differentiate between the instances as fast as I'd like).
I still think they should pop up a short tutorial when you first use it.
I decided "right, this is the new user-friendly desktop. Let's see how I go."
I literally couldn't find anything to click on to make it work. Literally nothing. The only button I could find was how to switch it off.
'I recommend this Dusk Till Dawn quote to desktop designers: "Are you such a loser, you can't tell when you've won?".'