The absolute easiest way to get the new Android O Beta is through the Android Beta program, since all you have to do is sign up and get an OTA upgrade. That said, some people like to do things the old fashioned way. Maybe you’re running a custom ROM, or maybe you just like starting with a clean slate. Whatever the reason, the factory images for Android O Preview 2 has now arrived.
Just like with the OTA program, the devices supported are limited to the Pixel, Pixel XL, Nexus 6P, Nexus 5X, Nexus Player, and the Pixel C. You can grab the OTA files via the link here. Not sure how to manually install these? Be sure to check out our Android O install guide.