How to Customize the Windows 8 Start Screen
Click in the screen’s bottommost-right corner to switch to a view of your groups. Then drag the groups into your preferred order.
The Start screen changes to show all your tiles as little clumps with each clump representing one group. Now that you’ve created groups of tiles to match your interests, you can shuffle them into any order you want. For example, you can move your favorite group to the screen’s far left, where it’s always visible.
Drag and drop the groups into the order you want them to appear on your Start screen.