Once you have completed the setup of the router, you can easily connect to AT&T router through your device settings. While setting up the router, it is important that you change the username and password of your router to avoid unwanted access to your network.
Steps to connect to ATT router:
Go to the Wi-Fi settings of your internet device.
Then, select the ATT wireless internet network name which you must have customized.
Now, enter the password for your network.
Then, click on connect.
The device will recognize the Wi-Fi network and establish a connection.
Read more: https://connectrouter.com/how-to-access-att-router-settings/