Installing KOMMA from the update site is easy!
At first you have to get a current version of Eclipse. In this tutorial I am using Eclipse 4.4 Standard for Linux (64bit).
Afterwards you can install KOMMA by clicking on Help > Install New Software. Use the following update site.
Check all items within the category RDF as shown in the picture below.
After restarting your Eclipse application you should finally be able to use the KOMMA Editor.
You can test your installation by switching to the OWL perspective. Just click Window > Open Perspective > Other
Now you can start playing with the KOMMA Editor.