The document provides instructions for animating models in Source Filmmaker using the graph editor, explaining that key frames are used to determine motion over time by placing the first key frame at the start of the timeline, adding a second key frame 100 frames later, and moving the model to create motion that will play between the two key frames when hitting play. The basics of the graph editor are covered, showing how key frames are the simple yet powerful way to animate models by marking positions in time for movement to occur between the frames.