Being a full-screen editor, vi must know your terminal type. If you are logging in from a CEC terminal, this should be handled automatically. If you have problems when you start vi, contact a CEC consultant.
The basis for vi is: display a file on the screen, and let the user move around and make changes to it. Note, however, that the editor does not make changes directly to the file you specify. It makes its own copy of the file and remembers the name you gave when you started. You do not affect the contents of the original file until and unless you write out your changes.
Read the man page for vi for more information. You can also view the man page in a Unix session by typing:
man vi
There is also a quick reference guide for vi available in the CEC office for a nominal fee.