Use this mode sparingly, when you need greater detail, as it can easily produce outlines with twice as many curves as outlines done in Smooth mode. When drawing with a mouse the two modes will appear very similar. The other Pencil modifiers should be self-explanatory. You can change the thickness , color , and style of Pencil lines with these modifiers. So far we're just drawing lines.
Lets add some color.
With the Pencil, draw a few closed shapes. Then select the Paint Bucket tool, and using its Color modifier, select a nice vibrant color. Click inside your outlined shapes to fill them with color. Often outlines drawn freehand will appear to be closed, but actually contain tiny breaks, so that when you fill the outline, the fill color floods into the surrounding area. Just as the Pencil tool draws lines, the Brush tool paints with fills.