Google has released Android P Developer Preview 3 (Beta 2) with added features, visual changes and new APIs allowing developers to create apps that support upcoming Android 9.0. Android P DP3 (build PPP3.180510.008) OTA update and factory images are now available for download, which you can install on a compatible device.
Google has posted Android P DP3 (Beta 2) images for the 2016 Pixel/Pixel XL and 2017 Pixel 2/Pixel 2 XL devices. You’ll also be able to install the new build on select devices from Nokia, Vivo, OnePlus, Xiaomi, Sony, and Oppo. Below is the download link and installation instruction for Pixel devices.
If you would like to know what is in store for Android 9.0, join the Android Beta program by going here. Upon joining, you will get the OTA update for the Android P beta. If are reasonably techy, you can also install factory images /OTA manually by downloading the required file.
Download Android P DP3 (Beta 2):
Pixel (sailfish) – Factory images/ OTA
Pixel XL (marlin) – Factory image/ OTA
Pixel 2 (walleye) – Factory image/ OTA
Pixel 2 XL (taimen) – Factory image/ OTA
Installation:
After downloading the required file, you may follow this step-by-step guide to install the build on your device manually. Before you begin, you should take the necessary steps to ensure all your data is backed up. [Source]