Hi.
After you import your model you need to make a scene from it.
-FileSystem > RightMouseClick on your model file> New Inherited Scene
Then you should see an animationPlayer . It shows any animations that come with your model. You then need to write a code (eg. for pressing spacebar) that will play and stop those animations.
You can first try Your First 3D Game. It will show you how to add code and play basic animation
And later on if you want a more complex animation control you need to add an AnimationTree. This allows you to do extra stuffs like blending of animations to look smooth..etc.