In this example, we will be adding a menu link to the mainmenu menu to display a static content page.
On the administration page, navigate to Menu > mainmenu from the top menu. Click on the New button on the top right-hand area. On the page that appears, click on Link - Static Content. Enter a name for the menu link. Select the static content page you wish to associate with the link from the Static Content box. If the link is a sub link, select its parent from the Parent Item box. Click on the Save button on the top right-hand area to create the link.