From admin Dashboard navigate to Appearance → Menus
Also you can assign menu to locations in Manage Locations section.
- Off Canvas (off canvas side menu)
- Logo Left/Top (header layout set to logo left or logo top )
- Logo Split Alpha (header layout set to logo split, on left from logo)
- Logo Split Omega (header layout set to logo split, on right from logo)
See Theme Options / Custom Layouts for more info.