Great app but..... – Dragon & Dinosaur Addons Free for Minecraft PE Review

Great app but.. I can't figure it out. I wanted the water dinosor one so I downloaded it then I went to mincraft got on to settings clicked it then I played it doesn't work!? All I want is to play with dinosors. That's all I really want. Help me
Review by I says no walk away on Dragon & Dinosaur Addons Free for Minecraft PE.