Here's the instructions from Phandroid.com.
A couple of things to note:
-You *may* need to make sure your build numbers match the expected build for the update (prepping for the update).
-You have to be patient. I know. That's the last thing you want with an early update, but it's true. I found myself waiting at several screens for more than 5 minutes while it did its thing. Just be ready for that. Don't reboot during any part of the update.