One of the simplest animations to make is a transition. They are very easy to make. They are the animations that are between every slide.
Here is a short video of how it is done in Powerpoint 2010:
How to make a transition:
1. Click on Slideshow on the menu, and then on Slide transition.
2. Click on a slide in the Slide toolbar (it should be on the left side of the screen by default), and then apply a transition from the new Slide Transition toolbar.