After you've placed the order, we assign a PRO player with Magic Rooster item in his inventory. He works according to the agreed schedule and will contact you in-game to trade you Magic Rooster.
As soon as you receive Magic Rooster you can learn it from your inventory, and it will become available to all the characters on your account. If Magic Rooster is the Blizzcon promotion code, you will receive a digital code to redeem at your battle.net account page.