Distribution
I'm fairly sure that Canberra (Directorate of Personnel in the RAAF example) contact PSA and request a certain amount of pilots for the upcoming courses which are then scooped from the top of the pool. From there, as far as I understand, you are essentially just waiting for the formalities of a letter of offer.
This info mostly comes from guys that have been through the process before and whom I currently work with.
Cheers and good luck to all. I hope too meet some of you in the near future (hopefully very near!)