The method for the S3/S4 isn't the easiest. There are plenty of YouTube videos available showing how the replacement is done and TBH this is one area I feel more comfortable paying a local repair shop to do the work. Yeah it blows throwing away money on having someone else do it but in the event something is damaged (like the digitizer) in the process its covered by them...
Main reason I say this is the S3/S4 display is glued down and involves a heating process to remove it and if your not very careful the digitizer can be destroyed.