Fire Stick doesn’t have “Unknown Sources” any more. How do I add new apps?
On AFTVNEWS their instructions are go to settings>My Fire TV> About>Fire Tv Stick 4K Max (this is my stick, your name may vary)> Click this name 7 times to activate developer options. Apparently this was done by Amazon to eliminate complaints from some users who had clicked on something that messed their sticks up, although god only knows what that click was.
Go to settings and do ok 7 times on firestick.