You have to complete all the tasks in the character menu. Then you'll have to teach swimming lessons for the student council, and I think that's it... sorry for my broken English. I'm using the translator because I don't know what order to use so I don't sound like I'm 5 years old.
Moved her after the quest of the club start scene on last school class period on morning. After completing this one, she must appear on the evening as a special button.
