First let's talk about what you'll see. There are three important screens. The first screen that appears once you log in is the Start Screen. The Start Screen has your live tiles, and it lists your installed programs—both Metro-style apps and desktop applications.
From the Start Screen, you can launch full-screen Metro-style Apps. This is the new style of app. You can run either one app full-screen, or two apps side-by-side. When you start a Metro-style app from the Start Screen, the app starts directly without you ever seeing the normal desktop.
Alternately, from the Start Screen you can also view the Desktop and any desktop applications you've launched atop it. Desktop applications include any program that runs on Windows 7. When you start a regular application from the Start Screen, the desktop appears and the application launches there.
Now the stage is set. How do we navigate around? For getting around in Windows, the most important key on your keyboard is the Win key, between Ctrl and Alt. In lieu of the Windows logo in any Unicode font, I'll just use "[Win]" to refer to that key.
If you want to start a new program, then from any screen...
- [Win]: Show Start Screen.
- [Win]+D: Show Desktop and any desktop applications running atop it. If you already have a desktop application open on your screen, this hides all open windows and displays the desktop. (Similar to the Show Desktop button in the Quick Launch bar of Windows XP and earlier.)
- [Win]+R: Show Run window. (This also displays the Desktop.)
- [Win]+W: Search and list apps, settings, and files.
- [Win]+Z: Show App Bar. This is a bar along the bottom of the screen that displays a list of app-specific actions. This is specific to Metro-style apps and the Start Menu.
- [Win]+I: Show Settings specific to the application, as well as general to the operating system. Here access the Control Panel, Personalization, and PC Info (System Properties from previous versions of Windows).
- [Win]+K: Show Devices.
- [Win]+X: The God menu -- the main menu for a power user. If you get tired of the modern synergistic Metro 2.0 paradigm, this is your blanket and cup of cocoa.
- Esc: Return to the previous screen. This may be a Metro-style app, or it may be your desktop with any number of desktop applications.
- [Win]+Tab: Switch between applications. This is very much like the Alt+Tab that you're used to, except it has a different appearance and treats everything atop of the Desktop as one item. If you have three Windows applications running atop your Desktop, [Win]+Tab will either switch to the whole set or switch to another full-screen Metro-style app.
- [Win]+C: Show Charms Menu and the clock. For a keyboard user, the Charms Menu just introduces a middleman between you and Start Screen ([Win]), search ([Win]+R), settings ([Win]+I), devices ([Win]+K), and Share ([Win]+S). I think it's intended for touch operation, where you would open the Charms Menu by swiping the right edge of the screen.