@Patrick433 Two suggestions:
1. Go to Melbourne city website and look up regulations about short term rentals unless you plan a 30 day minimum. In my small city all I needed to know about permits and regulations was easily available. I would think a large sophisticated city like Melbourne would have something similar.
2. Air BNB supports local Home Sharing Clubs and Melbourne has one. Go to Discuss, and select Home Sharing Club from the drop down box. There you will see Melbourne and you can join. Not only will you probably get your answers but also the mission of these clubs is support of hosts.
Good luck in this business!