You should read the manual, however here is a brief description of the files in
this archive:

Hex          - The program itself.
Hex.info     - Icon for above.
Hex.doc      - Manual.
h            - Keymap used by Hex. Copy it in DEVS:keymaps.
req.library  - A FreeWare library Copyright ©1989, 1990 by C.W.Fox and Bruce
               Dawson. Copy it in LIBS:.