LSE is a multilanguage, advanced text editor that is layered on the
  the Text Processing Utility (TPU).  LSE works with supported languages
  and productivity tools to enhance program development.

  There are three ways to execute LSE commands:

     Menus     DECwindows LSE has pull-down and pop-up menus for most of
               the common editing operations.  Use MB1 to choose items
               in pull-down menus and to  select text.  Use MB3 for
               pop-up menus.  See help on Menus.

     Commands  To type a command, press the DO key.  If necessary, LSE
               prompts you for more information, such as file
               specifications  or other parameters.  For a list of LSE
               commands, see help on List of Topics.

     Keys      LSE defines some keys by default and lets you define keys,
               including learn sequences, to bind several commands or keystrokes
               to a single key and GOLD key combinations.  You can use
               SET KEYPAD commands to set an EDT- or  EVE-style keypad.