As detailed in Menus, each menu item is linked to a Page Series. In the Page Series area of Evoke you can add as many Page Series as you need for your App.
Each Page Series is made up of Pages and, again, you can have as many Pages as you need in a Page Series. The Pages in a Page Series are all the pages that will be used in the functional area of the App, that is linked to by the menu item. You can create a new page that is blank or; if the same Page is used elsewhere in the App, then you can "Link" Pages, which means that any changes are reflected in all the linked pages; or you can import a copy of another Page, so that you can modify a copy of an existing Page to create a new Page.
Each Page Series has its own set of defined Data Sources.