Change wifi name to separate 2.4 and 5 networks

I have recently exchanged my old XB6 gateway for a new XB8 gateway. I had to have an agent activate the new gateway. I forgot I needed to separate the 2.4 band and the 5 band and need to do so as I have several devices that will only connect at 2.4. I went in the admin tool using my browser and it referred me to the Xfinity App. When I clicked on the wifi button at the bottom of the app screen, the app presented me with a sparse screen with no relevant options. In reviewing the online help, it says that settings are not available if advanced wifi settings are enabled. How do I disable these advanced settings so that I may change the wifi names to separate the bands? Attempts to use the assistant to accomplish this have been futile. I have been unable to trigger the assistant to put me in contact with a live person to help.