When flying into Schiphol (AMS) Amsterdam Airport, a direct train connection can take you from Schiphol in an hour to Dordrecht Central Station. For information on how to get from the train station to your accommodation, their website will provide you with the needed information.
Bonfire is ten minutes walking distance from Dordrecht Central Station. Many hotels are also walking distance from the Congress. Or you might want to try the ‘Dutch way’ and rent a bike, an option offered by some of the accommodations.