In order for your pokemon to level, you must explore the world. Each post you make post you make in the world counts as one Exploration Point. When you reach 20 ExP, your pokemon goes up a level, and you ExP reverts back to 0.
ie:
When your pokemon goes up a level, their stats change, they can learn new moves, and even evolve. To find out what your pokemon's stats are, what moves they can know, and when they evolve, simply check the Pokedex.
Your pokemon can know a max 5 moves, and 1 HM.
