- Turn on developer options by opening the system summary screen on your device (Settings > System > General > System Summary)
- Press OK on your remote 7 times. You should get a message stating that you're now a developer!
- In the same "System: General" menu, scroll all the way down to the bottom. You'll now see a Developer Options section, which should already be turned on.
- Scroll down and select "Force allow apps on external"
- You can now use ADB to upload your apps to the device.
If you need more info on how to use ADB, go here: