Where do Victoria's laws come from

Victoria's laws come from several different sources — the Australian Constitution, Victorian and federal legislation, and common law.

The Australian Constitution
Victorian and federal legislation
Common law

What's the difference between…

Legislation, statutes and Acts?

Nothing … All these words mean the same thing — laws made by parliament.

Commonwealth, federal and Australian parliament?

Again, nothing. All three terms refer to the Australian parliament in Canberra. You can find out more at the parliament website.
Australian parliament website.