Unfortunately Gazebo TV does not have a standalone app on the Firestick.
We can suggest a possible solution and work around for for watching Gazebo on the Firestick.
There is a screen mirror feature that will allow you to "cast" or "screenmirror" from your Phone or Windows Computer to your TV. If you have the technology know-how, this method may be a sufficient work around for you to watch on your Firestick.
To enable the "Screenmirror" functionality please follow the below steps.
Turn on Screenmirror on Firestick:
Hold down the Home button on your Firestick remote.
Then, select Mirroring to enable it.
Alternatively, you can also enable mirroring in Settings > Display & Sounds > Display Mirroring.
Screenmirror from your Android to Fire TV: Swipe down from the top of your Android device to reveal the Quick Settings panel. Look for and select a button labeled Screen cast. A list of devices on your network will show up. You should see Fire TV as an option to cast to.
Screenmirror from your iPhone to Fire TV: you will need to add the application "AirScreen" to your Firestick. Simply search for "Airscreen" on your Fire TV app store and download the app. Once the app is downloaded, open the app then follow the steps above to turn on screenmirror on the Fire TV. Play the GazeboTV video on your iPhone web browser and swipe up on the control center of your iPhone, select screenmirror and select the device that popups.
Here is a link to a 3rd party solution for screenmirroring to the Fire TV, which may also work for you: https://www.makeuseof.com/how-to-cast-to-fire-stick/
We realize this is not ideal but it is the only solution we have for Amazon currently.
You can contact firstname.lastname@example.org for any questions regarding the above information.