To edit the Navigation, go to Content > Pages > Navigation
Video Tutorial - Adding A Navigation Item
Create and edit the site navigation by using the simple drag and drop in the navigation module.
Parent - 1st Level
Parent (1st Level) navigation items display when the main navigation is expanded.
Child - 2nd Level
Child (2nd level) navigation items will display when the parent (1st level) is selected.
3rd Level navigation items will display when the child (2nd level) is selected.
4th Level navigation items will only be displayed in the sidebar navigation when a page template is set using the Subpage Default Template (full-width page templates do not include a sidebar).