Thanks for writing in!
To accomplish what you have in mind, please make sure that you added some unique ID in each of your section. For example, you have 3 sections with IDs, section-1, section-2 and section-3. In you menu, (Appearance > Menus), insert a custom link as your menu item and use
section-3 so that when the menu item is clicked, the page will automatically scroll to the specific section ID.
To properly set up a one page navigation, please check out this article: