To Open a new empty SignWriter Studio™ file (.SWS) which holds the Dicitionary and the SignList.
You can have several SignWriter Studio™ files on your computer. Most people will only ever use one. You can only open one file at a time. (However you can open SignWriter Studio™ twice and have each working in a different file.)
The Document menu is always available no matter whether or not you opened a SignWriting Studio™ File.
The next time you open SignWriter Studio™ the last SignWriter Studio™ File will open. This is so that you don't have to choose the file each time you start if you only use one file.