@sahamilton is correct in that tickets for October 2024 are not available yet. However, it’s not quite as simple as saying that all available flights will appear exactly 353 days out. Qantas (as of 2023) only flies to Italy (Rome) from 22 June to 6 October. They haven’t announced their 2024 dates yet, and there’s no point speculating whether they’ll fly into Rome over the same period of time, or expand the dates, or not fly at all. Pre-pandemic, Qantas was releasing award tickets to Europe a certain number of days out (depending on Qantas Frequent Flyer status); nowadays that seems to have changed and they seem to be releasing tickets in batches at random times (some announced, mostly unannounced).
So you’ll also have to consider Qantas partner airlines (Oneworld airlines and Emirates) and (as of 2023) they release their reward seats at all sorts of different times.
In the meantime, the best way to prepare is to do as many searches for award space as you can now, just so you have an idea of what may be available. You may well find, for example, that there’s more award seat availability into Milan than into Rome, and to/from Adelaide than Sydney.
Europe is a very high-demand destination, and flights out of Australia to Europe using Qantas points are very difficult to come by (as of 2023). I would absolutely recommend that if/when you see a suitable flight available, you take it immediately – don’t wait and see if something better comes along. And things will be likewise easier if you don’t look to book the outbound and return trip at once: book the flights as they become available.
Finally, be as flexible as you can. Search for flights not just out of the city nearest you but also out of adjacent cities (eg. if you live in Melbourne, search for flights out of Sydney, Adelaide and Brisbane as well). And search for flights not just into Rome and Milan but also Athens, Vienna, Budapest, Frankfurt, Munich, Zurich, Geneva, etc, etc. Be wiling to think outside the square (eg. by flying via places like Delhi, Columbo, Amman etc). The more flexible you are, the more likely you’ll find flights.
I’d love to know how you go!