Stop motion animation is animation that is captured one frame at time, with physical objects that are moved between frames. When you play back the sequence of images rapidly, it creates the illusion of movement. Like the early works of Disney, which was 2D drawn animation with each frame being drawn by hand and then played in sequence to create animation. Stop motion works in a similar manner except it uses photographs of physical objects instead of drawings.
If you look at the basic process of animation, it involves taking a photograph of your objects or characters and then moving them slightly to the next part of the action and then taking another photograph of the moved object. You keep moving the object through the different moments in the action and taking photographs. When you play back the images consecutively, the objects or characters will appear to move on their own.
Here is a story I created using stop motion animation in some parts of the story. The story is of a battle which takes place aboard a ship in the middle of the ocean between a ferocious dragon and a brave Knight in Shining Armour. Enjoy!