Track days are easy to get into,
You will need to be with a cams affiliated club,
https://www.cams.com.au/get-involved/clubs/club-finder Pick a club that isn't to demanding but has the scope for opportunity if you want to get more involved. Phillip Island Auto Racing club is good for me, you can "just be" a member or you could end up heavily involved in V8 super car days as an official.
Secondly your car needs to be in reasonably condition, put some Dot 5 brake fluid in ($20 to $30) and a secondary bonnet restraint and mount an in date vehicle fire extinguisher usually mounted in passenger foot well in arms reach of the driver. Some woollen clothes and a Helmet and finally a level 2 speed licence.
Now I have seen all types of cars hit the track from Porsche Cayenne to full blown race cars doing a shake down. You wont need semi's or big brake upgrades on your first few runs, how serious you want to get will come down to your wallet. I see a lot of old corolla's etc all striped out with back yard engineering way of brake cooling and chassis adjustments that cost nothing but your own time and how creative you can be. We can all be Larry Perkins!!!
There are a few come and try days around, you will get a level 2 speed licence for the day and become a temporary member of the club hosting for one day, it gives you opportunity to dip your toes to see what you think. And don't forget, just being a spectator is a really good way to get a feel of how it all runs. If your in Victoria go along to a Alfa romeo track day or a Wrx track day, both clubs run a pretty tight ship with the Alfa club getting a bigger variety of cars.