The Start screen is the brain center of your computer
.This screen is where you open apps and other programs, communicate with friends and family, and view the latest weather updates. You will obviously navigate away from this screen frequently to complete other tasks. You can return to the Start screen in several ways once you are finished using one app and need to access another.
The easiest way is to simply press the Windows key on your keyboard. This function will instantly return you to the last-used app in your system, which will be the Start screen in most cases.
The Charms bar is another way. The central toolbar for Windows 8 can be made to appear by swiping inward from the right edge of your screen. From there, click on the Start button (the Windows icon) and you will be returned to the Start screen. Another way is to use the Switch List. Swipe inward from the left edge and make a “U” back to the edge of your screen. This will reveal the list. Click the Start screen button located at the bottom.
If you are using a mouse, simply move your cursor to the lower-left corner of your screen. Click the Start screen thumbnail that appears to return there.