this is unityscript.

public var animation : animation;
/*You define this file on your game object, just drag & drop*/
function OnTriggerEnter(){
  animation.Play();
}

All you need to do is define your animation, and this should work. Hopefully this is what you're looking for.

Incase you're looking for how to export an animation into Unity, this can be tricky.

Unity only recognizes animations with models that have bones, along with having to be baked. I suggest using Maya or 3DSMax to do this. I'm not an expert on this, so I can't really give any tips on how to do it properly. You can find videos of how to use bones and how to bake on youtube probably.

Good Luck.