How do I wire 2 switches to control a ceiling light?
It sounds like two of your red wires form a switch loop to one of your switches. The remaining red wire is the hot (I believe called active in Australia?) coming into your ceiling.

By connecting them all together, you have wired your light (and switch) directly to your unswitched power, which is why it stays on. You'll need a multimeter, voltage tester, or electrician to determine which red wire is the unswitched active. 

If only one red is indeed active, then one of those two non-actives goes to a switch, and the other comes from a switch (or possibly to/from the same switch depending on how your two switches are wired). 


One of the non-active reds needs to get wired to the active red.
The remaining non-active red should become your switched hot leg that would ultimately need to be wired to your light fixture. 
You can use a multimeter or voltage tester to try this first-- if the switches don't work with the first combination you try, swap the two non-active reds and try your switch again.


If this whole concept sounds foreign to you, I recommend calling in some professional help (not the therapist kind).