i'd advise you to look at the syllabus, but basically there are 3 sections
1. opic called What is History and basically just you look at the different views of historians on history and debate things like - does history actually exist or is it just an interpretation of the past?
2. the Case Study. there are 25 (?) Case Studies which your teacher can pick from. they range from ancient things lik greeks, romans and histrocity of Jesus Christ to fairly modern things like Winston Churchill or my case study, which is the presidence of John. F. Kennedy. There are also 5 (?) Australian History case studies but i don't know how popular they are.
finally there is the section 3. which is The History Project. Basically you can pick ANY aspect of history you wish to study (so long as it doesn't overlap with the examinable content of any other HSC or SC exam, which is where its usually caught) and write a 2500 word essay on the historiographical point of the history. So usually, people pick something with historical debate to it. something like JFK's assasination is good because there is controversy and while JFK is a case study, we don't do his assasination.
oh and the history project is internally marked.
hope that helps, but i'd really advise you look at the syllabus for a more accurate description.
good luck