The detailed instructions will be in the post with the ROM download, but here ya go anyway........
*download the rom and place it on the root of your sd card. Meaning NOT in any folders, just on the sd.
*open bootstrapper. tap "bootstrap recovery" then tap "reboot recovery".
*using your volume buttons, scroll down to "backup and restore" and press the camera button.
*make sure "backup is highlighted. press your camera button and let it backup your current rom.
*when it finishes, scroll down to "wipe data/factory reset" and press camera button. then scroll down to "yes" and press camera button. let it wipe, then scroll to "wipe cache partition" and wipe the same way that you wiped data.
*when it finishes, scroll down to "mounts and storage" and press camera button
*if it says "mount/system" then press camera button and it will change to "unmount/system. do the same for "mount/data
*press the power button once to back out to the main menu
*scroll down to "install zip from sdcard" and press camera button.
*scroll to "choose zip from sdcard" and press camera button
*scroll down and find the rom file you downloaded. it should be near the bottom. press camera button. scroll down to "yes- install" and press camera and let it do it's thing. after it finishes you should be back at the main menu (if not, press the power button to back out to it). now scroll back down to "mounts and storage and do the opposite that you did earlier, meaning both should now say "mount/system mount/data" again.
*press power button to back out to main menu and press camera button on "reboot system now". phone will reboot with Liberty. I hope this helps
