How to configure Thread Border Routers into a single Thread Network

[bWayneNtampa]

I have 3 thread Border Routers (Nest Hub Max, Google TV Streamer, Apple TV 4K). Each is creating it's own network instead of creating a single network. How can I get all 3 on a single network?

[SmartHomeH-TAGS]

What would happen if you turned off 2 of those Border Routers?

I know very little (I've read some and seen YouTube videos explaining it) and no practical experience with Thread, but what if you added devices while 1 Border Router is powered on and then turned the other Border Routers back on?

I would think you would have to change the Border Router speaker into a powered Thread Extender like a Thread bulb or plug.

Multiple Border Routers...

https://threadgroup.org/Newsroom/Blog/multiple-thread-networks-and-the-seamless-interconnectivity-of...

[bWayneNtampa]

I tried shutting all down, factory reset and bring them back up one at a time. Apparently the Apple TV stores the credentials in iCloud and I haven't been able to overwrite with either of the credentials from Google.

[SmartHomeH-TAGS]

I didn't suggest to factory reset the speakers, just turn 2 of them off to see whether the Thread sensors, lights, etc. would continue to operate through the one Border Router.

[bWayneNtampa]

Ah. Devices that are attatched to the TBR do stop working. That is one of the problems I am trying to solve for.