After you have chosen your starter monster, you will begin your journey, flying across the mighty monster world finishing quests, missions, discovering new monsters, and defeating some treacherous foes.
Islands are mostly your goal to the game, there are three modes for each island, normal hard or heroic, to unlock the next difficulty finish all the quests the mode you are on. Each island has 2 or more cpu trainers you must beat to move on. You must beat islands to move on to next one but you dont need to finish all the modes just finish normal. Happy Questing!