Sometimes you will want to group your links inside a subnav under an unlinked subheading.
The subheading will appear inititially as a regular link with a downward caret to the right.
Once the user clicks on the subheading, it will expand to reveal its child links.
This subheading will need to be added in the Menu admin ui. In the top toolbar, hover over Structure, move down to Menus, move over to Main Navigation, and click on Add a link.
Enter the text to appear as the link title. Enter the link to the first child item in the Link field (do NOT enter <nolink>). Check Show as expanded. Select the Parent Link.
After you have saved the subheader menu item, then you may add the child menu items normally (by adding the pages to the menu system). Make sure to select your new subheader link as the Parent link for these child pages.