What is SpriteManager and how to I download it?

What is Sprite Manager and How do I download it, I am not a very good drawer at sprites. The Artist I am working with is a little busy at times. So I am using sample Sprites to Prototype games. I just need a better way to handle sprites while working with Unity, such as Sprite animation. I suck at making Sprite sheets correctly to do the animation. I wanna make a 2D game so bad. I just don't have that art skill. I researched and heard about Sprite Manager. Is this pre built into Unity, or do I have to obtain it from somewhere else. I found perfect documentation on it. Just have no way to access it.