After you have created or modified a timetable, you can save it to disc by choosing File - Save from the menu bar. If the timetable already has a name, it is saved under that name. If the timetable does not yet have a name, the Save File dialog appears so that you can select a name and location for the new timetable. The timetable is saved under the name you enter.
Should you wish to save a named timetable under a different name, choose File - Save As from the menu bar, and enter the new name in the Save File dialog.