First let's check, what model of camera is it?
I see you selected Nest Cam Indoor when creating your post, which is setup using the Nest app, not Google Home app. Please make sure you're using the correct app. Are you following the steps underneath "Nest app" in the help article below?
The app walks you through the setup. The camera has a QR code on the back. Scan the QR code on the back of your camera. You can also tap "continue without scanning" in the app and type the numbers at the top of the QR code.