Answer:
The leader of the Australian Government is the Prime Minister, who is a member of the House of Representatives. They are elected by their party to lead their team, and have the power to choose other members of the government for important roles. The Prime Minister gives areas of responsibility for how Australia is run—a portfolio—to selected members of the government who become ministers for that portfolio.
Members of the government who are not ministers are backbenchers. They do a range of work for the government, including researching, participating in committees, making speeches and voting on bills.