On the left navigation bar the first button is menus. When you log into the menu manager, you will be menus. If you are on another window select menus on the navigation bar.

Once in the menus window, you will see all of you existing, active menus listed. If you have service periods active, you will also see which service periods those menus are attached to.

To edit a menu, click the edit icon to the right of the menu name:

Once you are in the menu editor you can change the menu name, reorder/create/rename sections, add/remove/edit/reorder items as well as add menu headers/footers.