In Style Builder, you can set a few Preferences options:

The Sets pane holds all the strokes for your sketchy edge style. The strokes you place here are the ones that become part of your .style file. To add strokes to your style, first make sure the Sets pane reflects your desired sets and number of strokes per set. Then you begin filling and editing the Sets pane with strokes by using a few different commands. The following sections walk you through the details.