To install Apps that are not available in the Amazon Store or already pre-loaded on your Fire Stick or Fire TV, you will first need to download and install the Downloader App.
The Downloader App is a must-have tool for anyone looking to maximize the utility of their Firestick by accessing a wider range of apps and content. It is a popular assistant that makes it possible to easily download files from the internet onto Amazon Fire TV or Firestick. It’s particularly useful for installing third-party applications that are not available on the Amazon Store
Getting Downloader on your Firestick
Step 1. Press the Home button on your Firestick remote or remote app and choose the Find icon on the home screen.

Step 2. Type Downloader into the search bar and follow the on-screen instructions to install it.

Step 3. Enable Developer options on your Firestick, which allows you to download third-party apps using Downloader
Go back to the home screen by pressing the Home button.
Go to Settings > My Fire TV > Developer options.
and turn on “Install unknown apps” for the Downloader app.
If you can’t see Developer Options, go to Settings > My Fire TV > About, and tap on your FireStick remote seven times to activate Developer Options.
Update the ADB debugging and Apps from Unknown Sources from OFF to ON.
