On Unix, or a Unix like OS, you'd use "cron". For something
produced in Redmond, use "at". For details, read the manual
page. This is not a Perl question, you'd use the same answer
if you have a program written in Ada or Eifel, and you wanted
that to be run every 30 minutes.
Will the script be executing on an Unix machine? If so, check out 'man cron' and 'man crontab'. If you don't have access to the man pages, you can read them here:
Maybe someone else here can provide you with an answer if the script will be running on a Windows machine, or some other OS.