The first rule for lighting animation stop motion movies is Do NOT use natural light!  At least for close stop motion work like animating minifigures or clay characters. I know there are plenty of stop motion movies on youtube of people and objects outdoors during daylight hours..but that is a different kettle of fish altogether.   There is 3 point lighting and all sorts of positioning of lights and reflectors that you can read about anywhere on the web but I have found having tried a good few of them is that a single lamp with a piece of paper wrapped around the bulb can have very good results indeed. Be careful that the paper does not burn or catch fire obviously turn of the lamp when you leave the room for a break or whatever. The paper diffuses the light enough to avoid reflections or glare on your character for animation. It also means you can move the lamp up close to your subject confident that you won’t get any nasty glinting reflections.