The feature allows you to enable the category menu at the top. The categories appear automatically when you create them in the admin area. The menu appears instead of the "Home, New Products, Specials, etc." links at the top navigation. You can turn it on/off via admin area.
You can configure the template set via "Tools->Layout Boxes Controller" and "Configuration->Layout settings" sections in the admin area. To use the CSS buttons in the template you should enable "CSS Buttons" property in the "Configuration->Layout settings" section.