Windows 8 is not initially intuitive to use, so some short cuts are useful to learn to allow you to switch modes.
Here is a short list of five shortcuts.
Note: In case you’re new to keyboard shortcuts, all of these involve holding down the Windows key (it’s to the left of the space bar), then tapping the appropriate letter or function key.
Windows-C Immediately brings up the Charms bar, for quick access to things like Search, Share, and Settings.
Windows-D Switches you to Desktop mode—a place I suspect many users will prefer to hang out, at least initially. Once you’re in that mode, pressing Windows-D again toggles between minimize/restore all windows, same as in Windows 7.
Windows-I Brings up the Settings charm, where you’ll find—among other things—the Power icon for shutting down the PC.
Windows-PrtSc This handy new feature instantly captures a screenshot and saves it (in PNG format) to a Screenshots subfolder in your Pictures folder.
Windows-X Pops up a decidedly old-school menu of Windows tools, including Power Options, Device Manager, Disk Management, and Command Prompt.