There's product disclosure statements on the AMP and Commbank websites (and there's probably others). I'd rather they explain it than me, just in case I get it wrong (and I'm not a qualified advisor).
We went down this path with each of our kids as it didn't further complicate our tax returns. Nowdays you don't need to start with a large initial balance (some you can start with $0 if you set up a regular savings plan).