Talk to the kid hiding behind the basketball hoop beside the playground to start the quest.
1. In front of the Tower of Peace, behind a lamppost.
2. Inside the sewers
3: Left of Mr.Slave's garage
4: In the left corner of the cow ranch
5: In the upper trail east of Stark's Pond
6: Behind the desk in the bank.
After finding all of them, return to the basketball court and talk to them to complete the quest. They'll also become your friends.