http://www.airnieuws.nl/dsc/dsc.html
has all the specifics.
Note: NEW location,
in the new hotel building some yards south of the main passenger terminal/ Air Traffic Control Tower -but very near the Rotterdam Airport platform/"airside" general aviation.
Bus rides over the platform

See here:
https://www.facebook.com/stichtingairni ... 9830907117
Yes, you will have to register on the Saturday 23 April 2016 itself during the Aviation Fair.