You apply to the public sector organisation that holds the information. For example, the following are organisations: the NT Police, the Department of the Chief Minister, the Department of Justice, the Optometrists Board.
Before you make an application, you will probably find it useful to contact the organisation to talk about whether an application is necessary and the best way to word the application.
If the organisation you apply to does not hold the information or there is an organisation better placed to deal with the application, the organisation you applied to can transfer your application to the other organisation.
You can make an application as long as it:
Some organisations have their own forms for making an application. You aren't required to complete form to make an application as long as you satisfy the requirements of the application.
As long as you have provided contact details, the organisation will contact you if something further is needed.