@drobertson517
I remember getting very confused when I installed ours and got lost in the wires.
The two Nest Hello doorbells are NOT connected directly to each other, but the 2 Chime Connectors are connected to each other. Each Nest Hello, like your old doorbells, has one wire going to your transformer and one wire going to your chime. The wire from each doorbell going to the chime gets connected to each Chime Connector (instead of to the Front or Back screws on your chime), using the little clamp connector on the WHITE wire on the Chime Connector.
For one of your Chime Connectors (the one on the left in the diagram for the "Front" doorbell), the other little clamp connector on the GRAY wire gets connected to the GRAY wire from the other Chime Connector that does NOT have a little clamp connector.
The WHITE wire WITHOUT the little clamp connector on the first Chime Connector (for the "Front" door in the diagram) get connected to the "Front" screw, and the GRAY wire WITHOUT the little clamp connector gets connected to the Transformer screw on your chime.
On the second Chime Connector (for the "Back" door in the diagram), the WHITE wire that does NOT have a little clamp connector is connected to the "Rear" screw on your chime, while the GRAY wire WITH a little clamp connector is connected the wire going to the Transformer (the one that WAS wired to the Transformer screw before you started).
I think that covers it.
Your transformer has to have enough voltage, especially when powering 2 doorbells; we had to replace our old transformer. See this page for requirements: https://support.google.com/googlenest/answer/9247132?hl=en
Also, one of our doorbells wouldn't chime until we turned Chime Duration on (it's supposed to be for electronic chimes) and then turned it back off again. (Others have posted about this.)
