There are different types of charcoal such as vine charcoal, stick charcoal, and charcoal pens. You start by using vine charcoal to make an even grey background. After that you start drawing and shading with the different types of charcoal. the stick charcoal is the darkest and is the best for shading. The charcoal pen can be used for outlining and drawing small details. It can be very messy but with charcoal it is very easy to get dark values. Also, if you make a mistake you can just blend it into the background.