You will go to Terminal B, the level below baggage claim, all the way to the right. If you've done the transfer where they pick up your luggage for you, just proceed straight to that level with your booklet and tickets. If you forget your booklet, they have a desk that will take care of it for you. If you're concerned when you get there, either look for cast members wearing Mickey hands or any airport personnel can direct you to the correct area.
I can't remember is Southwest is in terminal A or B but there are giant neon signs when you get off the little train/shuttle to the main airport terminal.