There are several kinds of text editors available here.
E is the display editor in current favor.
SOS is teletype oriented.  If you will be using the display
facilities at the lab, learn E.
We also have DEC's version of TECO, but it is an old version
which will not work well on this system.

To learn E, use the monitor command: HELP ETEACH

SOS is described in SOS.LES[S,DOC], and briefly by HELP SOS