How to correctly flash this rom :

A) Backup your current system

1) Flash the latest recovery (see http://www.drakaz.com/forum/viewtopic.php?id=6 ) Mirror
2) Boot in recovery mode
3) Use nandroid backup to make a backup of your current system

B) Flash with Galaxo

1) Flash the latest recovery (see http://www.drakaz.com/forum/viewtopic.php?id=6 ) Mirror
2) Reboot in recovery
3) Push the update.zip on your internal sdcard (adb push update.zip /sdcard/update.zip)
4) Push the official JC6 PDA update on the sdcard renamed as SAMSUNG.tar on your internal sdcard (adb push YOURJC6UPDATE/sdcard/SAMSUNG.tar)
7) Wipe using the recovery
Flash the update using the recovery
9) Restore Gapps using the recovery
11) Reboot
12) Enjoy

source: drakaz.com