Melbourne is the best supported city in Australia in terms of activist movement infrastructure. So there are a lot of great sites and information for activists in Victoria.

Victoria (VIC) Legal Support: A Black Lives Matter protest in Melbourne
A Black Lives Matter protest in Melbourne

CounterAct supported the development of the Melbourne Activist Legal Support. This is a network of volunteer lawyers and legal activists who provide legal support, training and field human rights observers to protest events. They have an excellent series of resources themselves.

We wrote this legal guide for climate activists in 2015. We then adapted it for Queensland, and it was taken over by the excellent Action Ready. Whilst some information is dated, it's a great approachable guide that can be crossed checked with more recent legislation.