Hi there and welcome to this community. Initially, not much will happen on that budget assuming the best earn rate at 1 point per dollar, you’ll be accumulating only 400 or so points per month. HOWEVER …
My advice is to start by concentrating on either Qantas or Velocity and stick with just one for some time. Get yourself in the habit of paying everything with your credit card and most importantly, paying the entire balance before the due date. You will be offered bonus points along the way plus you will pick up points when you fly.
This will put you in good stead for your future. Don’t use your points to buy things or pay charges against your card, accumulate them and use them for flights. I would also recommend you subscribe to the free email course offered on this website. It will teach you the basics and the more advanced methods of collecting points.
If you haven’t already done so, get a credit card with ‘sign up points bonus’ and be aware that (provided you maintain a good credit rating) you can apply for a new card at ‘appropriate intervals’ picking up more bonus points.
Best of luck.