The Australian property market is kind of like a big game of buying and selling houses and apartments all around the country. Imagine you are playing a game with your friends where you have to buy and sell toys - this is like the grown-up version of that.
Lots of people in Australia want to buy a house or an apartment to live in, or sometimes they buy one as an investment that they can rent out to other people. When people want to buy a house or an apartment, they have to make an offer to the person who owns it and then pay them money (this is called a "sale").
The amount of money that people offer for a house or apartment depends on lots of different things, like how big it is, how nice it looks, and where it is located. Some places are really popular and lots of people want to live there, so the houses and apartments in those places are often more expensive. Other places might not be as popular, so the houses and apartments there might be cheaper.
The Australian property market is always changing - sometimes people want to buy lots of houses and apartments all at once, and other times, not as many people are interested in buying. When lots of people want to buy at the same time, this can make the prices go up because there is a lot of competition for the houses and apartments. But when not as many people want to buy, the prices might go down because there aren't as many people to compete with.
Overall, the Australian property market is a big part of the economy in Australia, and it affects lots of different people - from those who want to buy or sell houses, to those who work in the real estate industry, to even the government who makes rules about buying and selling property.