From Univention Wiki
Before you can start with the creation of an App for Univention App Center, you'll need to prepare your UCS environment. This section guides you through the necessary steps.
First of all, get yourself a copy of UCS free of charge at the Univention Website. You can choose between an ISO image or a pre-installed virtual machine.
Please refer to the UCS Quickstart Guide for the steps about installation and initial setup.