Can you please be a little more specific so i can help you on the points you don't understand or do you not understand any of the process?
the instructions state:
1. Place update.zip on SD card.
2. fastboot boot recovery.img
3 [optional]. make a backup with nandroid
3. apply update. (LET IT FINISH, DO NOT TOUCH ANYTHING UNTIL YOUR PHONE IS COMPLETELY IDLE. DO NOT TOUCH AFTER FIRST REBOOT (WHEN CHIP APPEARS) UNLESS YOU LIKE A BRICK.
)
4. HOME+BACK to reboot out of recovery mode.
5. power off phone, hold camera button and power to boot into fastboot again
6. fastboot flash boot boot.img
7. fastboot flash recovery recovery.img
8. fastboot reboot