Whenever you send your character AWAY (through the door icon in the upper right corner of the screen), s/he will practice with the band at the studio.
At 5:00 PM, 6:00 PM, and 7:00 PM your MusicStar will beep, calling your character to a concert. The band will perform a concert when you respond.
At 9:30 AM the band manager will appear carrying a bag of gotchi points with him. The number of gotchi points seems to be related to the number of times your band practiced at the studio and performed concerts.