Ring the GEelong Courthouse first thing Monday morning and make an appointment. Is it you that the boy is annoying, or your son? If it's your son, he needs to go down with you and you (as his mother) can make the application on his behalf.

The Children's Court sits at Geelong - same magistrates etc as the Magistrates' Court, same building - they just announce "Children's Court" at the start of the case rather than "Magistrates' Court".