How To ... Save
When you have finished editing something, just click MENU (the middle mouse button) and a context-sensitive menu will appear. Either directly from that menu or as a sub-menu from 'File' (follow the right-arrow after 'File' to open the sub-menu) a 'Save' option will be offered. Some applications (where the file has already been loaded and so its full pathname is already known) will allow a SELCT click on 'Save' to save the file directly (if the filename is unknown some applications will open the 'Save' sub-menu at this point; others just ignore the click). Otherwise move right over the 'Save' option to open the 'Save' dialogue box. The 'Save' dialogue box comprises a window, showing an icon (how the file would be shown in a filer window) that should be dragged to the destination on your disc. There will be a writeable text icon that allows you to specify the filename. Navigation to find the place you want to store your file takes place outside of the application.
The first time you do this, you will think "Curses! I've carefully typed the filename I want but I forgot to open the directory window I want to drag it to!". All is not lost as you can drag it to the disc icon on the icon bar and it will be saved, with the name you gave it, in the root directory of that drive. The other thing you might want to do is to use the 'Save' dialogue to drag the completed document directly into another application on the icon bar or to an open document window to insert the content into another application (or, indeed, the same application).