When you want to create a new drawing, use either the New or the Templates command in the File menu. Selecting New displays a blank page; selecting Templates presents a choice of various categories of templates, with several selections each. You can also create templates and save them to the My Templates category.
Designer lets you have as many files open at one time as your computer's memory will allow, each in its own drawing window. The title bar of a new window displays "Untitled1" until you save the file with a specific filename. If you have more than one unsaved document, they are named Untitled1, Untitled2, and so forth.
In addition, you can open multiple windows for the same document to view a different page in each window. You can even view the same page in two different windows.