(Please consult the README to check that you have a new enough version
of Perl.)

If you use a new-ish CPAN.pm which automatically follows dependencies,
the following should suffice:

  $ perl -MCPAN -e 'install MySQL::Diff'

Otherwise ...

You can install MySQL::Diff, as you would install any perl module
library, by running these commands:

   perl Makefile.PL
   make
   make test
   make install

Note that the test suite will not run properly unless you have
a MySQL server which it can connect to.

If you want to install a private copy in your home directory, then you
should try to produce the initial Makefile with something like this
command:

   perl Makefile.PL LIB=~/perl

If you want to use the command-line based front-end mysqldiff.pl, you
should copy it to somewhere on your $PATH.