Install Cast reactor on a fire tv
Activate developper Mode
Follow the tutoral below to enable Developer Options on Fire TV Stick
Install Downloader on Amazon Fire TV Stick
On the Home Screen, click on the Find option. In search results, choose the Downloader app.
Click on the Download button and wait for the app to install. When the app is installed, click on the Open button.
Install Fully kiosk browser
Open downloader App
Paste this url: https://dashboard.castreactor.com/fireTv.html in the text field
Click on "Fully Kiosk Browser APK ver. 1.50.1 (for Android/Fire)"
It will install the Fully Kiosk Browser app
Then follow this guide
Optional Install Fully kiosk browser
With downloader app navigate to https://dashboard.castreactor.com/fireTv.html Then click on "Launch on Boot"
After installation start lauch on boot and select "Fully Kiosk Browser" as the start up app