[Koha] Upgrade from Koha 3.00.00 to 3.0.6

Good Day All, I would like to know how I can start the upgrade process from Koha 3.00.00 to Koha 3.0.6 [Kindly keep in mind that our version of Koha 3.0.0 has a lot of in-house changes] What steps should I follow? Resources to read? I know there is the subversion vendor branches merge that I can do, but I am unsure if that will work and be sufficient. Kindly awaiting your response, Best Regards,