1) Go to CWM based recovery (PhilzTouch Recovery in recommended) by holding HOME - POWER - and VOL UP BUTTON
2) FULL WIPE is highly recommended!
3) Mount everything (System, Data, Cache..)
4) Choose "Install ZIP from sdcard"
5) Choose ROM zip file
6) Go through AROMA (Choose only what you want to install)
7) Wait for finishing flashing
8) Reboot and enjoy