The first step in using the Online Navigation Manager is to ensure that you have read/write permissions applied to the Editor folder. You may need to ask your web host to do this for you.
This is so the menu can be created and updated whenever you make a change in the administration.
To get to the Navigation Manager select the Occasional Tasks tab and mouse over the Navigation option and click on Site Menu Set Up:
The following screen will appear:
This screen allows you to modify any of the existing menu items, create new menu links and also update sub menu links.