After you install an app, you won't see it on your home screen right away. Go to your Apps section (the grid of apps at the top of the screen). Scroll down to "See All" and find your new app. You can even move it to Favorites for quick access.
So, what are you waiting for? Grab your Firestick remote, get a little curious, and start exploring. The internet is your oyster—and Downloader is the pearl knife. Happy sideloading!