How to Customize the Windows 8 Start Screen
Move related tiles next to each other.
As an example, you might want to keep your people-oriented apps — Mail, People, and Calendar — next to each other. To move an app to a new location, drag its tile to the desired spot. As you drag the tile, other tiles automatically move out of the way to make room for newcomer.
When you’ve dragged an app’s tile to the desired spot, drop the tile to set the tile into its new place.