Make an application to the responsible authority: usually your local council.
In some circumstances the Minister for Planning is the responsible authority, for example, for certain applications within the City of Melbourne. You can find the responsible authority for your planning scheme in the schedule to Clause 61.01.
The responsible authority will decide the outcome of your application. If they agree with the proposed land use and / or development they may grant a permit or - if there are objections - issue a notice of decision. The responsible authority may also refuse the application.