Before you download an app from a casino, some may ask you to allow installation from unknown sources in your device's settings. The APK file can be opened to start the installation process after it has been downloaded. You might be promptedrummy all app download to allow permissions before the installation can start, depending on the settings on your device. Getting the Games and Finishing the Installation. The installation will start as soon as the required permissions are granted, and in a short while, you'll have a variety of thrilling casino games at your fingertips. The download & installation process can be made even more convenient by using the APKs that certain online casinos offer directly through their website or app store.