Cannot upfate to Kodi 17

I just got nexbox 912 and it has 16. I went into playstore to upgrade to 17 and it only gives me options to open or uninstall. I’m very new to this and scared if I uninstall it I won’t be able to get it back installed. What should I do ? I have no idea how to sideload it? I have 6.0 popcorn