You can change the placement of the Primary and Secondary Menus by moving either the primary to the top, or the secondary to the bottom. This can get them positioned next to each other if you wish. You can also fix either to the top of the screen. The “standard” layouts place the two above and below the header image. If you just need to switch the order, then assign the menus to each in opposite order from the Dashboard Menu.
These options are in Customizer -> Layout -> Menus.