(only addressing this part, as the other comments have the important part covered)
I feel like this should be a legal obligation, that we are all given this kind of information in a flowchart. But I can’t find it. Can anybody help?
I'd say the Australian Electoral Commission is the most authentic resource for getting facts about our election (seeing as they run it). I wish some of this information was shoved in our faces more.
The information sheets PDFs linked on this page summarise how the vote count works: https://www.aec.gov.au/learn/preferential-voting.htm
Further reading: The preferential voting system we use in Australia is Single Transferable Vote (with the House of Reps using Instant-Runoff Voting ~~with optional preferences~~. IRV is just a single-winner version of STV), but you'll often hear it just called 'preferential voting' here (other preferential voting systems exist, e.g. Borda count).