In order to set up the plugin to access your contract rates and start printing labels, you need to obtain the following information: Account Number, API Key, API Password.
After completing the registration, Australia Post will reply within 24hours, and in case the application was approved, they will send you an email with a PDF file that includes your API credentials information. If you do not receive an email from Australia Post within 24 hours, check your spam folder or contact Australia Post customer support via firstname.lastname@example.org.
After you get the API credentials, add them to the settings page of Labels Pro. [Labels Pro] Label Printing and Contracted Prices Credentials