Wordpress Menus

Menus are collections of links. Your site may have multiple menus depending on your site's theme.

They are structured hierarchically, like a tree allowing you to have submenu items in places where the theme makes room for them.

Menus can be edited through Appearance > Menus in the Wordpress dashboard.

Choose a menu to edit with the dropdown near the top of the page then you can add Menu Items by selecting them and using the  "Add to menu" button.

Now the Menu Item has been added you can move it into the place you want with drag and drop to reorder items (you can also make it a subitem of another menu item), when you're done hit that "Save Menu" button.

Your menu is now updated on your website.

More details about menu editing can be found at https://codex.wordpress.org/WordPress_Menu_User_Guide