Users must allow installations from unknown sources in their device settings after downloading the APK file. Installing apps that aren't from the Google Play Storepatti rummy is made possible by this essential step. To accomplish this, go to your device's security settings and turn off the "unknown sources" option. The APK file is being installed. Users can find the downloaded APK file in the file manager on their device and tap on it to start the installation process if this setting is enabled.