simple animation which css:
When you create a picture you don't usually "program" the image. You use an image editing program like Photoshop or Paint.
Likewise when creating animations, in the sense of cartoons or movies, we do not normally program them, simple web animations aside, we use animation software.
For 2D cell based animations try Pencil2D.
For 3D animations try...
All of the above are free software. Professional studios use very expensive software such as Maya and 3DS Max.