A couple of days back Harrison Hoffman who is the Senior Program Manager at Xbox posted on Reddit to say that Google Assistant is now available for everyone to try out.

It is extremely easy to setup by doing the following:

• Join the Xbox for Google Assistant Group with the Google Account you intend to use
• Sign into your Xbox
• Open the Settings menu on your Xbox
• Select Devices & Streaming
• Select Digital assistants
• Check the Enable digital assistants checkbox
• Open the Google Home app on your iOS or Android device
• Select ‘+’ located top left
• Select Set up device
• Select Have something already set up?
• Search for and select Xbox
• Sign in with the Microsoft account you use on Xbox
• Follow the instructions to link your Xbox and give it a device name
• After your Xbox One and Google Assistant have been paired, you should be able to control your Xbox One by saying, ‘Hey Google’ followed by any of these commands:
  • “turn on Xbox”
  • “turn off Xbox”
  • “pause on Xbox”
  • “resume on Xbox”
  • “volume up on Xbox”
  • “take a screenshot on Xbox”