You're going to regret asking this but simply...

GA is expensive.

Forget anything as simple as the FAR/AIM. It's not as insane as the EASA regs but Australian regs are written by lawyers for lawyers. You'll probably have to pay for a course to make sense of them.

The following cannot be understated....Other than push forward, go down. Pull back, go up, everything is different. Expect to have to relearn how to communicate on the radio, for example. Oh and don't get me started on their screwed up airspace.

There are flying clubs but a lot have gone out of business over the last few years. I can give you a few leads but it'll depend on where you're thinking of living.

If you're really thinking of moving down under, don't even think about it unless you're going to get 130k if you're single or at least 200k if you have a family. We paid 500k in taxes and rent for the 5 years we were there. Came back last year and very happy we did.