yeah, you won't notice any difference in the way phone looks or operates, you are just turning the security back on (keeps from flashing unauthorized roms/files and other system changes).
Yes then you would put the 2.2 file on the root (not in any folders) of your sd card. The file has to be named exactly PB31IMG.zip and your sd card has to be formatted to FAT32. Boot into hboot, the phone will see the file on your phone automatically and ask if you want to apply the update by pressing volume up. You will see a blue progress bar on the right side of the screen fill up, your phone will reboot and start applying the update, Takes between 10-15 minutes to finish.
When in Hboot at the top left of your screen, you will see where it says, "s-off" or "s-on"