Sorry, but that is a Google Cloud Project Guide and not a guide on how to install Assistant Relay in Docker. If you don’t mind, I’d like to request your assistance to get this running in docker as well as how to call it from HA (how to pass commands). But perhaps we should go somewhere else with this discussion? Perhaps here: Assistant Relay - Third party integrations - Home Assistant Community (home-assistant.io)
Unless you rather not be bothered 