On Android device, navigate to 'Apps' > 'Settings' > 'Security', enable 'Unknown Sources', then tap 'OK' to agree to enable this setting. This will allow the installation of third party apps and standalone APKs.

Enable Unknown Sources: By default, Android devices only allow installation from the Google Play Store. To install an APK, you need to enable "Unknown Sources" in your device settings. Go to "Settings" > "Security" or "Privacy" > "Unknown Sources," then toggle the switch to allow installation from unknown sources.