Move the mouse pointer to "File" and click on it. You will get a sub-menu. Now click on "Save As". As the picture shows, you may not start out in the default directory of the command prompt window. Use the various controls at the top of the "Save As" dialog to navigate to the subdirectory you want (the default directory).

Navigating to the default subdirectory will be similar to the same task with Microsoft Word or other application program. You may need to go up the file hierarchy and then down to the default subdirectory. See next page for a picture of NotePad's file navigator.