Stopping an animation

Hey all, this is quite a basic question, but here it goes, I have an animation, which contains 12 layers, I want the animation to stop after it has ran through, but I do not know if i should create a seperate layer for the action? If so where does it go? Or if I should put the stop on one of the specific layers.

Also how could I create a playback option?? So the user could click on playback and it would play the animation (like a controlled loop)