If you don't see them, go to Windows > UI Elements > Time Slider and Windows > UI Elements > Range Slider. The Time Slider and Range Slider sit at the bottom of your main Maya window. You can specify which frame is the current frame, and how many frames fit into a second. The timeline allows you to move through time, showing one frame at a time.

In order to make another keyframe, you must 'move forward' in time. Once you make a keyframe, Maya stores that data for one moment in time. On the computer, timing is a bit arbitrary. Time in traditional animation is decided by how many drawings, or cels, you have. Besides implying that you have your own subordinate to do all the dirty work, this means there are essentially two ways to control your motion: your poses, and the interpolation between your poses.

When working with the computer, you create the keyframes, and the computer does all the in between frames. Drawn in 1914 by a man named Windsor McCay, Gertie the Dinosaur is widely regarded as the first animated cartoon.

Maya animation examples