[Koha] Upgrade to 3.4.1

Hi there This is my first post to this list. I am the responsible for IT systems in a Benedictine monastery, I am NOT a librarian. I set up Koha for the first time last summer - it is version 3.00.06.008 running on Ubuntu 10.04. It has been in use by the monastic community without any real problems since then. However I now need to upgrade to the latest version of Koha (3.4.1). Are there STEP-BY-STEP instructions of how to go about this? Thanks Greg