To download the GCash app while in Australia, visit the Apple App Store or Google Play Store on your mobile device. Just search for 'GCash' and click on the download button. Once installed, you can create an account using your mobile number. For a seamless experience, ensure you have a reliable internet connection and check if there are any specific requirements for overseas users. If you have questions during the setup, it's best to reach out to GCash support for assistance.