Elara has one main menu location “Main Menu”. This is the top header menu right under the logo.
To set this up, go to Appearance > Menus, add a new menu, and assign it to the “Main Menu” location. You can add posts, pages, custom links, categories, etc. to this menu. For more information on how to create menus, please read https://codex.wordpress.org/WordPress_Menu_User_Guide.