I managed to install Enterprise Manager OPS Center 12c (based on the step by step description of Gokhan Atil http://www.gokhanatil.com/2012/04/how-to-install-oracle-ops-center-12c.html)
Next I started to see how I would be able to integrate EM OPS Center 12c with my EM Cloud Control 12c and Oracle VM Manager 3.0 Installation.
Integrate Enterprise Manager OPS Center – Cloud Control – OVM