First of all, you need to concatenate plum-top with plum-bottom.
Make sure that you have an __END__ marker in the middle, and 
a reasonable #! line at the top.  If your system won't do #!, 
you probably better delete the __END__ marker.  Make it executable.

Now for the hard part.

The most challenging aspect in installing plum is getting system
dependent features working, you know, little things like retrieving
just one character without echo.  It would be nice if 1) everyone were
1003.1 compliant and 2) perl had interfaces to the tty-affecting POSIX
calls.  Unfortunately, right now neither is the case.  So we make do
with a system-specific configuration file.

The systems where plum is likely to run just by typing "plum" are BSD
systems that have had h2ph and c2ph run over the appropriate files in
/usr/include.  That leaves out enough folks that a better solution had
to be found.  Included here are several sample system configuration
files that contain canned answers for various systems.  It's much
faster to run these than traverse all the needed include files even
though you have gotten [ch]2ph working.   These conf files are named
conf_BSD.pl, conf_Sun.pl, conf_SYSV.pl, etc.  One and only one of these
should be installed in $PLUMLIB/sysconf.pl, where PLUMLIB is defined
either in your environment or taken from one of the first few lines of
plum proper.  By default, this directory is /usr/local/lib.  If none of
these files matches your system, make one that does, and then PLEASE
mail it back to me.

You probably want to make the file $PLUMLIB/plumaddrs world-writable
or else run it once as someone who can write it.  This will speed up 
startup of your program.