Go to your computer or phone and connect with your router & open browser and type 192.168.0.1 in the top url bar. It will ask for your login information (default username and password is admin & password simultaneously). Then it will open setup page. Just go to the wireless tab and from there you can change the channels for the wifi networks.
> connect your computer or smarphone with the arris router's network
> then open your browser and type this address:- 192.168.0.1
> then it will take you to the login page of the arris router
> type the login information(default username is admin and password is password)
> once you are succesfully logged in
> then go to the wireless tab and from there you can change the channels for the wifi networks.