Here you will find answers to those specific supervisor questions.
Providing that you hold the equivalent to a current Queensland open licence, and you have held this for more than one year, you may supervise and approve their drives. You cannot however instruct if you are on probation, hold a restricted or suspended licence, or hold a Learner or provisional licence.
They can have a number of different supervisors approve their drives. In fact, RACQ encourages having a number of different supervisors whilst they are learning to drive.