Here's how you can rename app groups on the Windows 8 Start screen. 1. Zoom out by hitting Ctrl- or by clicking on the minus sign at the right bottom part of your screen. 2. Right-click the group you want to rename. 3. Click the Name Group option at the bottom of the screen. 4. Type in your new group name.
For more, see the original article at the link below.
HDG Guide to Customizing and Organizing the Windows 8 Start Screen | Help Desk Geek