To create a new page, with no content selected in the document, click the Create New Page button in the Properties panel.
To edit page properties like size and orientation, click the Edit button in the Page section of the Properties panel, with no content in the document selected. To stop editing page properties, click the Back button at the top of the Properties panel.
To duplicate a page, in the Pages panel (Window > Pages), you can drag a page thumbnail to the Create New Page button at the bottom of the panel.
In the Pages panel, drag a page thumbnail to reorder it in the document.
To delete a selected page or pages, click the Delete Selected Pages button (trash can) at the bottom of the Pages panel (Window > Pages).