Add second menu to header. Step by step. (Dawn theme)

Hello.

In Dawn theme I would like to show two menu in Header (Logo → Main menu → Menu 2 → Search button and cart). Now it’s: Logo → Main menu → Search button and cart.

I create second menu “Menu 2”, but in the Header control panel I can choose only one menu at one time: “Main menu” or my “Menu 2”.

Please, could you explain which file in “Code edit” I need to change and how to add “Menu 2” to it?

was this ever solved?