You start off choosing either the Autobots or Decepticons. If you choose Autobots you will start off with Jetfire and human named Melody, if you chose the Decepticons you will start off with Starscream and a human named Luca. After completing tasks you are rewarded with a warrior crystal. Crystals are used to unlock new Autobots and Decepticons. If you are an Autobot you will receive Ironhide, Bludgeon if you are a Decepticon. You will then have to complete the first Campaign, at the end you will be rewarded with either Optimus Prime or Megatron, depending on your faction.