Yes you would need the Google home app to see the video, you can also see it on a nest hub, or through home.google.com. but you need the app to install the device anyways so use that :). You can share access with family members in the app as well yes.
For hearing it , nest speakers, hubs, will announce visitors if you activate that in settings as well. Make sure that the doorbell and the speakers are in the same home in the app.
