If cannot load file manager or kodi onto Firestick or Tv use Android phone method outlined below:
On Fire Stick/TV go to>System settings.>“About,” hit select, > “Network” and make note of the IP address. You cannot connect a Fire TV Stick to a PC with a USB cable (PC won’t see stick), so have to connect over Wi-Fi, and that’s where that IP address is needed.
Download from google play store the app “Apps2Fire “ onto your phone ,insert the IP address you noted for the stick ,then download onto phone the file manager ES explorer,the Kodi app and whatever repositories or programs you are interested in . Then upload same to the firestick through the Apps2Fire. Navigate to SD card (that’s what the internal memory on firestick is called) to downloads to ensure they are there and start install of the manager apk and then Kodi. Once that’s done you will have to navigate to Kodi and set it up within by installing your repositories and programs from the zip files etc. Kodi forum has guides on how to these installs. The above method worked for me as the Apps2Fire worked on my phone (it may not work for all). I spend a lot of time using other methods to try to add Kodi to stick via windows computer and found it frustrating and it worked only once (otherwise the computer registered no connection to stick so couldn’t add Kodi program).