You can do any type of animation you want for your short, but stop-motion is probably the easiest to get started with. Having said that, it still takes time and planning. Below are two short videos explaining one artist's process for making stop motion. He shows his process in a few different programs, but you can search YouTube for tutorials on how to do this in the specific program you use. I'm including the series below because this guy gives a great but short explanation of how the process works.