When tokens are sent out via the Xbox Live messaging service, you'll need to redeem said token in order to play the beta.
It's very straightforward and here is how you'll enter you'll find and enter your beta code once The Coalition starts sending them out to beta testers:
- Turn on your Xbox One
- Sign into your account. Use the same account that you qualified for the Early Access period with.
- On the Home screen, double tap the [Xbox Guide] button, or move your [Left Analogue Stick] to the [Left]
- Go to the Messages area of the Xbox Guide (this is the third icon down in the Guide)
- Look for a message sent by the Xbox Live team
- Select ‘Redeem Code’ on the message from the Xbox Live Team
- Select ‘Confirm’ to start downloading