It's very much on-the-job training.
The Senate department does some training for senators. When I say “training”, it's orientation courses for senators. They also are able to call upon departments and the audit office to give them briefings on particular things they're interested in and to take them through how the public accounts system works.
Basically, it's on-the-job training. They learn from their colleagues and they learn from the estimates hearings themselves. Their attitude is that if they don't understand the estimates then it's the public servants' job to help them understand and to get them to a point where they do understand. They'll keep asking questions until they understand.