The file ftp://thumper.bellcore.com/pub/nsb/mm27dos.zip contains only
the MS-DOS executables for metamail.  The manuals are included in the
metamail source code distribution available in the same directory.
If you don't want to download the source code package, here is quick
guide to installing metamail on your MS-DOS system.

- Put the metamail.exe program in a directory in your PATH.

- Edit your AUTOEXEC.BAT file and add the line

        set mailcaps=c:\yarn\mailcap

- Create a file named c:\yarn\mailcap using a text editor.  Put this
  line in the file:

        text/*; list %s

  This configures metamail to run the list program to display text
  Content-Type's.  For all other Content-Type's, metamail saves the
  message to a file.

- Add this line to the mailcap file to automatically launch the cshow
  GIF viewer for the image/gif Content-Type:

        image/gif; cshow %s