mountaindewgamefuel.com - you must register an account here
https://us.battle.net/login/login.xml?ref=https://www.worldofwarcraft.com/account/&app=wam-you must go here, log in, and set yourself up with a battle.net account
https://us.battle.net/login/login.xml?ref=https://us.battle.net/account/management/redeem.html%3Fkey%3D30e66dfed4d50331274d20af4dbf1143%26expire%3D1244689244000&app=bam-you must go here and enter your login info (via battle.net account)
once completed you will recieve an in-game mail on each of your characters with the pet.
Otional step-repeat last step each day to acquire fuel for your pet via in-game mail. (note you can pick either color of fuel even after choosing a side to ensure you can make your pet battle others.
Side note: The mail only lasts until the next time you Acquire something. For example: you get battle bot day one you get blue fuel day 2. Any character's mailbox you did not take the battle bot from prior to redeeming item for blue fuel will not have the battle bot but will have the fuel.