The Apple Menu, represented by the small Apple icon at the far left of the menu bar, has two purposes (which are standard for most Macintosh programs). The first entry in this menu is "About xFunctions". This command will open a window containing some basic information about the program (author, version number, etc.). It also contains the name of the file, if any, that you are currently working with. This is the file that will be rewritten if you choose the Save command from the File menu. (It can be a file that you opened with the Open command or a file whose icon you double-clicked on to start the program.) A file for this program will contain a list of functions and their definitions, and possibly information about the location and contents of a number of windows. When you open a file, the list of functions and the windows that were in place when the file was saved will be restored.
The Apple Menu also contains the name of any desk accessories that are installed on your computer. You can open an accessory by choosing its name from this list.
If you are running Multifinder on your Macintosh, the Apple menu will contain additional entries that can be used to switch from one application to another.