For those of you who want to root your AT&T Galaxy S3 SGH-I747, here’s a step-by-step guide plus video tutorial (using SGH-I747). Anyone with even slight knowledge of computer should be able to do this easily. This guide is noob-proof and my suggestion is to follow the video and the guide one step at a time.
Step 1. Hold Down Volume Down, Center Home, and Power buttons together for about 10 seconds.
Step 2. When your phone resets (screen goes off), let go of the Power button but keep holding down the other buttons.