So, you want to install a custom ROM on your newly rooted(wedded) Galaxy S3?
Well, I’ve been flashing custom ROMs on many different Android devices in the past and here’s my “universal” guide “fail-proof” method for installing a custom ROM on your rooted Galaxy S3. This will work on all custom ROMs.
Before you install a custom ROM, PLEASE MAKE A BACKUP ROM!!! See How to Backup/Restore ROM on Rooted Galaxy S3!
Also, before you install a new custom ROM, use Titanium Backup app to backup all your apps, use GMail to backup your contacts (make a dummy GMail account if you don’t have one), and use any SMS Text backup app from the Play Store to backup your SMS texts.