If you go RAAus, you'll need to pass 5 theory exams throughout the course of your training, and complete at least 20 hours of flight training, but realistically expect to be doing a little over 30 hours, it is competency based so the CFI will sign you off when you are ready. Hourly flight training rates are typically between $200 to $300 per hour. Your school will probably recommend you purchase a pilot kit, which should include your text books you'll need, and maybe a pilot log book, or at least tell you what you will need and where to get it. They will also want to get you to get your Student Pilot Certificate, about $240, within the first month of you starting your training.Your first step would typically be a trial introductory flight. Your instructor will take you up for fly, and hand you the controls for parts of it. I would recommend you then schedule 1 hour long lessons at rather regular intervals, like every one, two, three, or four weeks, or as your finances allow. Just bear in mind that if you leave your lessons too far apart, you tend to be playing catch up a bit, so in the long run you may take a little longer to get through it.
I kicked off my training May 2015 and earned my RPC in Feb 2016, so I think my advice may still be relevant.