not sure if you guys figured this out but it was driving me nuts just picked up a new TV from amazon one of there tvs with fire tv built in. I could not find it anywhere. I did find a work around to install it. not too hard but only recommend this if you know what you are doing.
1: go into settings and allow install from unknown turn on adb debugging this can be a bit different depending on model but should be under device and settings somewhere or developer options.
2: Go back to your Fire TV’s home screen and click on the search icon
3: Now, type Downloader in the search bar and select the result
4: Select the Downloader app from this list and finally click Download!
5: Open Downloader
6: Click Allow for the app to access your storage
7: Now click OK to proceed
8: Navigate to the Browser tab, in the left menu
9: Click on the search bar and enter the following URL: – tv.aptoide.com – and click Go
10: Scroll down and click Download Aptoide TV
11: When the download is finished, click Install to install Aptoide TV, the alternative to Google Play Store on Fire TV
12: After installing, click Done and Delete to delete the installation file and free up storage space
13 Open Aptoide TV and search for "VET TV" download and install
P.S.
During this process you may have to go back to your developer options and allow install from those specific apps that we are using to get vet tv installed on the device. After this process is done you can go back to those options and turn off install from unknown devices or completely uninstall them as to protect your self from accidently installing something you don't trust.
Hope this helps those that are frustrated with not finding a way to install it. No need to ever use the browser again