Constructor Theme Menus

I just switched over to the Constructor 1.3.1 theme. Only one problem with the header menu. When I add a custom menu, the original menu stays resulting in two menus. I really need the custom menu because I am adding some html pages from outside of the blog and need the child/grandchild option for those. The theme customizer tells me to do this in widgets under “header sidebar” but there is no header sidebar.
Help anyone!