I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.
Are you using the same account in the Nest app and Home app? Once setup in the Nest app, it should show up automatically in the Home app? Maybe check at the bottom underneath "local devices"?
To connect it to Alexa, follow these steps: