[AT&T, Rogers, Bell, Telus Samsung Galaxy S III] :
Read this carefully

First of all I just want to let you know there are hundreds guys, like you, that don't bother to read the installation instructions and then beg and plead for the forum to fix your problems which the disclaimer states that the OP is NOT responsible if you brick your device or cause damages to it. Second, if you bothered to read the "Rules" for the forum you would know that the General section is meant for such and the Q&A(Questions and Answers) section is meant for such. Please read something. At least once. Please.

I'm not burning you man all I'm saying is calm down and have patience with flashing custom roms because as you found out it can, and will, brick your device, sometimes permanently.

Okay now back to business, the "Odin" program(version3.07) I believe, don't quote me, does NOT work on a Mac at least to my knowledge.

If you have a windows xp computer please get on there and download the Odin software then go to here, http://samsung-updates.com/device/?id=SGH-I747, and then while that is downloading go to the AT&T Galaxy Slll Android Development section, not the "Original" section, and download the [Samsung Galaxy S3 QCOM ToolKit v2.3] and install it.

After it's started and it asks to update type, yes, and press enter. After that is finished press the number, 1(one), for AT&T SGH-I747 and then enter. If you have the drivers installed already skip this step, if you don't have the drivers installed press the number 1(one) and install.

Afterwards you can press the number 8(eight), Download, Extract + Flash Stock ROM via Odin, then after entering the #8 section select #2.

In this section it asks you to put the Stock ROM into, put_odin_images_here, which can only hold one file at a time.

Go to your downloads folder, on your PC, and drag the Stock ROM file onto the desktop. Next go to my computer and locate your Samsung Galaxy Slll QCOM program files, check where you downloaded it to, and then click on the folder to open it.

You should see something like...

backups

drivers

INPUT

mods

OUTPUT

etc.

Drag the Stock ROM to the put_odin_images_here folder and then go back to the Galaxy Slll QCOM program.

Type the letter, R, to refresh the list and it should show 1 file found and also FILE NOT FOUND(ignore this message).

It asks if the file you put into the folder is the one you want to extract. Type, yes, and press enter.

After it's finished it will put the extracted file into OUTPUT, I believe =P, and then you return to the QCOM program.

Go back to the main screen and then press number 8(eight) then enter and then press number 4(four), Flash Stock ROM via odin, press enter.

Press the number 1(one) and let it do it's thing. If it doesn't want to enter your custom recovery then skip this step.

Afterwards press the number 2(two), Flash Stock ROM via odin, and then follow the steps.

If this doesn't work for you consult with the original poster of the ROM in a private message and let him know that you screwed up and that it's your fault for not reading and you would really appreciate his help.

I'm sorry I seem mean about all of this by the way it's nothing personal and in fact I was treated much worse back in the Sprint Epic 4G Touch forums way back when and I learned a lot from their criticism.

Keep learning the terminology and skills and you'll get it down soon enough.

A bit of advice as well...don't flash a ROM that isn't the same O.S. level as your stock phone. (Ice Cream Sandwich stock/ ICS custom ROM)