You'll want to be familiar with sideloading apps on the firestick first before doing this next part, if you care to anyway. Maybe try this out on your pc first with a windows install of kodi.
You can make the firestick a fuller media system, able to stream things from a wide variety of sources, by giving it a new face. This goes for any kodi install actually, they all work the exact same. Visit http:// spartanpixel .net and try out The Beast for firestick (lots of stuff), or The Royalist (small install, mainly the good stuff). There's tutorials on how to install it on the site.