Click on the File Menu and select Open to open an existing drawing in the main application window for editing.
Select the file location in the Open Window and then click on Open located in the bottom right corner of the screen.
The selected file will appear in the main application window as part of the Drawing Canvas.
Note: A recently created or edited file can be opened by clicking the File Menu and choosing Open Recent. To clear the current list of recent drawings, click on Clear Menu at the bottom of the menu.