Notice Important: Don't delete Menu with ID is 1, it is this menu:

1) Please make sure you created the menu item in admin, please go to admin MGS -> Manage Megamenu Item and Menu is "Main Menu"

2) If you created the menu item as above but the menu item is still not showing, try Flush Menu Cache and Refresh Magento Cache, go admin MGS -> Manage Megamenu Item:

3) If you are using Claue theme and want to use the header with logo center in menu, refer this document:

http://www.magesolution.com/themes/claue/docs/m2/index.html#add-logo

Also note: if you edit menu item/create menu but it doesn't reflect on the frontend, you only need Flush Menu Cache!

4) You want to add New label on parent menu item like this:

you only need to add the "Special Html" for menu item:

5) You want to add the label in subcategory, like

You only need to go to CATALOG -> Category, edit category then click "MGS Megamenu" and add: