The conference will take place in Groningen, at the Ordina building. The address is:
How to get to Groningen?
Although Groningen has an airport with several touristic destinations, flying to Schiphol and taking the Train from there is most likely your best option. Trains between Schiphol and Groningen go every half hour (departing between 6:04 and 23:04), take just over two hours, and should cost at most 25,- for a single trip.
Within the Netherlands, use the dutch planner for the public transit.
Participants from Germany may want to travel by bus or train via Bremen.