I don’t know of the camera works I only have the thermostat. You can read everything here : https://community.home-assistant.io/t/i-made-a-crappy-nest-thermostat-integration-that-will-work-as-a-stopgap-until-alternatives-come-out/139270
It was a little hard to understand how home assistant works. But you can find everything on Google . So it’s not to hard I had it fixed in a small day. I made a script for this kind of things and homey just pushes to home assistant to strat the script.