Content > Pages > Navigation

Related second level links display in a drop down menu.

Content > Sections

The custom sections are added to the drop down menus through  the "Sections" manager. The "Sections" manager can be found under the "Content" tab in the main navigation.

A naming convention is used to associate sections to nav items.

The menu looks for a "Section" titled "Nav Section -  [Link Name]", where link name "[Link Name]" is the exact name of the corresponding link title.  

For example, the "About" section would have the section labeled "Nav Section - About".