Go to Settings from the home screen after turning on your FireStick.
Open Developer Options from My Fire TV.
Disable Apps from Unknown Sources and activate ADB Debugging.
Navigate to Find > Search from the home screen.
Navigate to the Downloader app from the list of results by typing the word into the search field.
Get the Downloader software installed, and Go to Settings.
To make certain websites function, you may need to enable JavaScript.
To obtain the HDO Box APK file, input the URL into Downloader. With a different device, look for the HDO Box APK link and enter it into Downloader after that.
APK file will download when you click "Go."
There should be a prompt after the download is finished. Once the HDO Box app is installed on your FireStick, select Install.
To return to the Downloader app after installation, choose Done. There, you may remove the APK file to free up storage.
Take a look at Your Apps & Channels on the FireStick home screen once again. HDO Box should be listed there. Start streaming by opening the app.

Wrapping Up

Ways to Get HDO Box on iOS (Sideloadly IPA), on PC (Nox Player), & FireStick (Downloader)