Adding Google Nest WiFi Pro Extenders to Xfinity Wifi Network

I bought the Google Nest WiFi Pro system about a month ago with the intention of extending my Xfinity wifi network throughout the house for better connection/coverage. When setting them up, it looks like we created a second wifi network rather than extending the existing one. Now, our connection is even worse and both networks are spotty. I want to delete the new one and just use the Google pods as extensions of our original Xfinity network. How can I do this?