I'm not really sure what you are trying to do but.
To loop an animation, you just set Loop to Yes, inside the animation editor. (select the sprite, then under Properties, click on Animation Edit) Pick the animation and there will be a Loop options with a dropdown box, change it to yes and the animation will loop.
If you are using the Default animation then it will just play, and loop itself. If you created a new animation, you will have to use an action to start the animation.
-On State of Layout
Sprite: Set Animation to "Test" (Play from the beginning)
Then it should loop.