Open a page from Pages under Website. In the page editor, open Address and Navigation.
Choose Main menu or Footer to add the page to those links. Choose Not linked for a page that people reach through a direct link. A published, unlinked page remains public.
Lower Order values come first. Use Navigation label for a shorter menu name. Select Save Settings after a change.
Address and navigation settings apply immediately, even while page content is still a draft. Check View Site after changing an address that visitors use.