Installing
I've just written a guide with screenshots on how to Install this Domino Designer Plugin (attached).
Using
Once the Plugin has been installed in Designer, you can follow the bundled Readme to perform an Import/Export of various elements of a Project through the Eclipse "Navigator" view. The Plugin either Exports to File or to an OpenNTF Reusable Control zip bundle (includes LICENSE and NOTICE files), and likewise can Import from either file or Reusable Control zip, or directly from the online OpenNTF project repository.
Niklas has also created a video on how to use this plugin here: http://www.youtube.com/watch?v=tLIkgbtkUiQ
Hope that helps!
- David