Installing an APK package

Amazon FireTV Stick

Find Amazon’s APP Store
Find search (In the APP store) and enter downloader
You should see an APP called Downloader, click that
Download the APP
When it’s done downloading, click Open
Allow Downloader access to photos, media, and files on your device.
Click OK at the start-up screen
Enter the URL of the APK package (You either find that here or get it from support)
You might be asked to approve the Downloader to be able to install unknown Apps. To do this go to Home > Settings > My Fire TV > Developer Options > Install Unknown Apps > Downloader (Should now say ON)
Now go back home and find the App again (Downloader)
Unless the App was closed you should be able to continue and simply click Install (If not, go back to Enter the URL of the APK …)
Follow the instructions on the screen
When the installation is done click Open

Go to Google Play Store (Go to APPS in the top menu)
Search for downloader
Download Downloader by AFTNews
Open Downloader by AFTNews
Enter the URL of the APK (You’ll find the URL here)
The downloader should start the download of the APK and automatically open it when it’s done.
You might have to do additional steps, but they should be displayed when the APP launch.