If you have completed an accredited Australian undergraduate law degree (LLB) or Juris Doctor (JD), you will need to complete a recognised Practical Legal Training Course (such as the Leo Cussen Graduate Diploma of Legal Practice [GDLP]) or equivalent.
Following this, you can apply to be admitted within your Australian state, noting that the requirements for admission are slightly different in each state. You must satisfy the admitting authority that you are a 'fit and proper' person, which involves disclosing certain things, such as fines and offences. After this, you will attend the Supreme Court for your admission ceremony, and be admitted as an Australian lawyer.
If you hold an overseas law degree, you will need to contact the admitting authority in the Australian state where you wish to practise. The admitting authority will assess your overseas qualification, and inform you of any additional study you must complete through an Australian institution. This might include university subjects, or a PLT course.