1. Swipe down from Notification bar, then select the Settings icon.
   
2. Select the CONNECTIONS tab then select Data usage.
   
3. To change the displayed billing cycle, select the Data usage cycle drop-down.
   
4. Select Change cycle.
   
5. Select the Desired date and select SET.
   
6. To set a monthly data limit, select the Set mobile data limit checkbox.
   Note: When the mobile data limit is active and has been reached, the mobile data block will remain in effect until mobile data is manually re-enabled on the device, the limit threshold is changed to a higher value, or a new data usage cycle begins. If you set data usage limits on your device, they do not communicate with AT&T systems. You will still receive AT&T system generated notifications as you approach your data limits.
   
7. Select OK.
   
8. Drag the Warning marker up or down to set the level at which you will be warned about your monthly data usage.
   
9. Drag the Limit marker up or down to set the monthly data limit.
   Note: The data warning and limit will save automatically.
   
10. Scroll down to view a breakdown of Data usage by application.
    Note: To restrict individual apps from using data while running in the background, tap the Desired app > Restrict background data switch. To restrict all apps from using background data, from the 'Data usage' screen, tap More > Restrict background data. Your myAT&T account is another way to manage your wireless usage.
    
11. You can also view your data usage through AT&T All Access. To open AT&T All Access, from the Home screen, select the AT&T folder.
    
12. Select AT&T AllAccess.
    
13. In AT&T AllAccess you can view how much data you have used in your plan and set a notification when you get close to your limit. Select and drag the Alert icon to the desired location. 
    
14. To change AT&T AllAccess settings, select the Settings icon.
    
15. Edit Settings as desired.