Shutter speed is how long the shutter on your camera opens and closes. If you have a lot of light your shutter will open and close really fast, and vise versa. The faster the shutter speed the sharper your image will look.
Use a fast shutter speed when your taking a picture of something moving fast. Use a slow a shutter speed when you want a blur in the back round and to be focused on the object your photographing.
Aperture is all about death of field. That just means how blurry or sharp the background is in your picture .
Using 100 ISO will give you the crisp image you want. But in low light conditions a higer ISO will make up for that.