The code for this module is a lightly modified mashup of the core "section header" content type and the Content Aliases module (as a lightweight example of how to create/clone a content type without hacking the core). So thanks to those devs. After installing the module, you will have a new section header content type available called "Subsection Header". First you must import the menu or menus you are using in your template into the database via the menu manager. Then, also in menu manager, in your newly imported menu template, duplicate and subsequently alter the duplicated sectionheader related smarty and html by adding "sub" in front of "sectionheader". Then use it the same way you would use the section header content type and style it differently in your style sheet(assuming that's the functionality you were seeking).