You can invite traffic controllers to your event in several ways via Verkeersregelaarsexamen.nl:
A unique access code for the event. You can manually forward this code to the traffic controllers.
Can be used at all kinds of events, when there is a shortage of traffic controllers. An appeal is made to active traffic controllers who have indicated that they want to help in the regarding municipality.
To be used at larger, recurring events with fixed group(s) of traffic controllers. Read more about the contact list here.