1. download and install srsroot from
SRSRoot One Click Root for Android (SuperUser)
2.put your s3 in debuggind mode look here :
Samsung Galaxy S3 : How To Enable USB Debugging Mode - YouTube
3. conect the phone to computer and install drivers, after the instalation is complete
4. run z3x soft, select your model, scan for phone, when the phone is found press direct unlock
5. enjoy your unlocked phone
