From the web page that is displayed, look for the Wi-Fi settings. The channel number should be selectable via a drop-down menu . Note that if your router does work on 2.4GHz and 5GHz, you will have to choose the channel separately for each.
Read moreWhat is the best channel number for WiFi?
Which channel is best for WiFi? Channels 1, 6, and 11 are the best channels for WiFi in the 2.4 GHz band because they are the only non-overlapping channels available.
Read more