As you start doing the main questline in The Indigo Disk DLC, you'll eventually need to meet up with Carmine at the Central Plaza, which is right in the middle of the Terarium, connecting the four biomes. Speak with her, and you'll be introduced to Drayton, one of the BB League Elite Four members. He'll take you to the League Club room back at Blueberry Academy. You can get more Throwing Styles and change them out in this room.