Unfortunately, I can't seem to find eNotes study guides that pertain to this particular topic. However, my fellow Educators have answered questions that are related to your exam's specific subject. I've included the links to the resources at the bottom of the page.
In the first reference link, an eNotes Educator explained why Australia became involved in the Vietnam War. In the second reference link, another eNotes Educator provided reasons why Australia supported the Vietnam War. For a more authoritative and detailed summary of the Australian government's involvement in the Vietnam War, you can read the Australian Army's publication for a conference regarding this broad subject. It is listed as the third reference link below.
The Australian Army sent over 60,000 military personnel to support the South Vietnamese Army. The Australian government—like other Anglosphere countries such as the United States and the United Kingdom—was anti-communist and believed that the Australian government should contribute in preventing the spread of communist power in the region.
In total, the Australian Army suffered over 500 casualties during the Vietnam War and an estimated 3,000 were wounded in action. The Australian government spent over $218 million to support the war.