To install the factory images, you’ll need ADB Fastboot properly installed, the process will wipe your Nexus 5 or Nexus 7 clean. If you’re really hankering for some Android but don’t want to lose all of your precious data, you might need to sit back wait for a while. Hopefully, a few custom ROMs with the preview base will become available for other devices as well.  Another thing to keep in mind is that these images are not final, hence the ‘preview’ status. Neither are likely built for daily use could have quite a few bugs. So, if you’re just looking to check out the new Android build, make sure you backup your phone first. If you’re ready to flash, head over to the Android Developer site.