To open the navbar on the editor do this
You can change the links by clinking on the menu item concerned and doing this
If you want to rename a menu item, double click on it and rename it.
If you want to create a new menu item, click on
Nav Link and copy/paste, then change url redirection and name.
To change background image select
And click on Image and Gradient, Background image, replace
Notice that the old image was 727X1333px
Hope this helps,