First up, we'll need to enable
Apps from Unknown Sources. This tells the Firestick that it's okay to install third-party apps.
Open Settings and choose Device (newer models will say My Fire TV instead of Device).
Under Developer Options, select Apps from Unknown Sources and set it to ON.
To download the app from the Kodi developers, we'll use another app called Downloader. Thankfully, this application is available on the Amazon Appstore.
To download this app, look under the Utilities category in the Appstore.
Using your Fire Stick remote, navigate to the Downloader app and launch it. Open Browser from the left-hand navigation menu. Enter the following address:
Scroll down and select Android from the list. You can choose to download the 64bit or 32bit version. Feel free to experiment with both to see which works best for you. I'm installing the 32bit version.
Once the version you selected is downloaded, a pop up will ask you to install the package.
You can now open Kodi from your main menu. It will be listed among your current selection of apps. When you access Kodi for the first time, it will prompt you for permission to access media files and folders. Be sure to give it the permissions it needs.
Now it's time to add some media! Visit the official Kodi wiki for help adding your own videos, music, and more. This Video library page is an excellent starting point for understanding the Kodi menus and how to add your own media library.
Updating Kodi on the Firestick is easy.
Remove the current version by going to Settings > Applications > Manage Installed Applications.
Select Kodi from the list. Choose Force stop then Uninstall.
Open the Downloader app and navigate to the Kodi downloader URL:
Select the latest Android version to download and follow the installation prompts. Congratulations! Your Firestick now has the latest version of Kodi.