You need to learn some basics first, ill help you with some basic terms and knowlage. Your exposure is how long your camera stays open allowing light to enter and make the image, to long open will over exspose a pic hints reason why some pics are white. Your apitcher (sp) is how wide your camera lense is open... meaning the mmore light let in. What is your iso first off?
Another quickie you wont have the same apitchure and shutter speed (real term for exosure) for most pics. Each pic is unique in setting due to you wont need a longer shutter speed cause what your shooting is lit better, or you wont need a wide apiture because its lit well. Lighting is the biggest roll in photogerphy, maybe because in greek thats what photogephy mean " writing with light"