See upstream README file for configuration and usage instruction.
Almost all information from that file is relevant.  However, from
the section "INSTALLATION", only this is relevant:

  * To be performed in place of 'make initdb' from the README's installation
    instructions.

    Initialize the database

      rt-setup-database --action insert --datafile \
         /usr/share/request-tracker5/plugins/RT-Extension-RepeatTicket/etc/initialdata

    Only run this the first time you install this module.

    If you run this twice, you may end up with duplicate data in your
    database.

    If you are upgrading this module, check for upgrading instructions
    in case changes need to be made to your database.

  * Edit a file like e.g. /etc/request-tracker5/RT_SiteConfig.d/90-local and
    add (or update, if a similar entry already exists in /etc/request-tracker5)

      Set(@Plugins, qw(RT::Extension::RepeatTicket));

  * Clear your mason cache

      rm -rf /var/cache/request-tracker5/mason_data/obj

  * Add rt-repeat-ticket (it's installed in the default PATH) to a daily cron job
    in /etc/cron.daily/* .

  * Restart your webserver

 -- Joost van Baal-Ilić <joostvb@debian.org>  Tue, 20 Sep 2016 20:35:21 +0200