Airport Time Capsule Third Generation Roaming connection with a Google wifi router

I am trying to make a internet configuration to improve my wifi in the whole house, but I don't want to switch between different wifi names, I have a Airport Time Capsule Third Generation, Google wifi Router and a modem, my house is two stories and my basement, where I need internet signal too. My Problem; I have my modem and router in the same room, and I was able to connect an ethernet cable to my Time Capsule, so far so good, but I can make the Time Capsule extend my wifi connection. I read that doing a roaming configuration would be perfect in this case. However, I don't have the whole explanation to do that. When I connect the Google router and the Time Capsule, my understanding is I have to put in a bridge mode, but if I only do that and switch the wireless setting in the Time Capsule off, then the Network option goes off (bridge mode); too, but at that point the Time Capsule is not doing any internet wifi capabilities, to turn that option I have to go back to the wireless setting and chose the network Mode to Extend a wireless network and leave the name and password as they are, unfortunately if I do that my Time Capsule goes flashing amber, the google wifi goes amber too and the internet goes amber too. Could you help me to solve this?