The actual steps will vary depending on whether you are making a joint or sole application and whether or not you have children under 18.

Complete an Application for Divorce
We recommend using the automated version at familycourtforms.com.au.
Sign it before a lawyer or Justice of the Peace
You must swear or affirm the Application for Divorce before a lawyer, Justice of the Peace or other person authorised to witness affidavits in your state or territory.
Make 2 copies
Make two photocopies of the completed and signed Application for Divorce and any supporting documents.
Lodge it at a Family Law Registry
You will need to file the original and two photocopies of the Application for Divorce and any supporting documents along with a copy of your marriage certificate at a Family Law registry. You will also need to pay the $432 fee or request an exemption or waiver.
Get your hearing date
The registry will give you a file number and a date and time for the hearing. They will also give you sealed copies of the application (ie copies that have the original court seal stamped on it).
Serve documents
Serving documents is the process of delivering or posting court documents to the necessary people after they have been filed, in accordance with the rules of the court. Essentially, making sure everyone has received the documents filed with the court. If you've made a joint application then you and your spouse each keep a sealed copy of the application. If you've made a sole application then you need to serve the necessary documents on your spouse.
Attend the hearing
If there is no child of the marriage currently under 18, you are not required to attend the hearing. This applies to both sole and joint applications. If there is a child of the marriage currently under the age of 18 and you made a joint application then neither you nor your spouse are required to attend the hearing, however, if you made a sole application then you must attend the hearing.
Get your Certificate of Divorce
If your divorce application is successful, the Court, will grant the divorce order. The order becomes final one month and one day after it is made (unless it is shortened by the Court). At this time the Court will send a Certificate of Divorce to you and your spouse individually, or to your lawyer if you have one.

You should allow a minimum of 3 months from filing your application before expecting to receive your Certificate of Divorce.