Why does my keyboard disappear while i am using it?

[tamies tablet 2017]

Am i using the correct keyboard for my tablet? I know there are several different ones. PLEASE HELP ME. IT HASNT WORKED SINCE I GOT IT AT THE END OF JULY. I

 

[B. Diddy]

Welcome to Android Central! Are you certain you're not accidentally tapping the Back or Home buttons in the bottom nav bar?