Set up your device for the first time or after having done a factory reset.
INSTRUCTIONS & INFO
To setup your router, connect your device to the router's Wi-Fi network. The network name and password are visible on the screen and underneath the battery. Note: Before setting up your device, make sure you have completed the online activation process. Please see Activate phone, SIM card, or other device for more information. For more information on how to connect your device to a Wi-Fi network, see your device's tutorial on AT&T Device Support.
From the connected device, go to http://attwifimanager from a web browser. Enter your new mobile router password, confirm your new mobile router password then click NEXT. Note: If you do not want to change your mobile router password, click SKIP then click YES.
If desired, enter a new Network Name and/or Password for your Wi-Fi Network. Click NEXT.
Click FINISH to complete setup. Your device is now ready to use.