The Android O developer preview has been available for about 2 months now. As the name implies, it’s mainly for developers. It’s not super easy to install if you’re not familiar with the SDK and all that stuff. The Beta Program is much easier for the average user to install. It’s rolling out right now to Pixel and Nexus owners.
Android O Beta Program is available for these devices:
If you have one of those devices, all you have to do is visit this link and click “enroll device.” A system update will soon arrive on your phone. Simply install the update like you normally would. That’s it!