: Navigate to Settings > My Fire TV > Developer Options and enable Apps from Unknown Sources before using a "Downloader" app to enter the APK URL directly.

: Only download APKs from trusted sources. Downloading files from unknown websites can expose your device to malware or security risks. Install and add files | Android Studio - Android Developers

To download and install the Foxi APK, you must first enable "Unknown Sources" on your Android device to allow installations from outside the Google Play Store.

: If you are using an Android emulator on a computer, you can often manually install the APK by dragging and dropping the file directly onto the emulator screen.