Google released the developer preview of the latest version of Android yesterday. This build is meant to be used solely by developers so they can begin preparing their apps and games for the final build of Android O which will be rolled out to devices later in the year. Normally a Developer Preview is not ready for primetime and includes lots of broken things and bugs. This is great for secondary and backup devices if you want to just see what Android O is all about, however I would not suggest installing this on a device you actually rely on for day to day use.
If you still want to install Android O the method for installation isn't all that difficult. You will need to have your bootloader unlocked and need to be familiar with adb commands. You can find downloads and lengthy instructions at the link below.
via AndroidAuthority