Don't forget to replace "client_name" in the above line to your client_name, for example: brakkegrond.
Now you can invoke the functions in the script:
So if you have an event with event_id 95 you can launch the order screen like this:
Optionally you can add a session_id, an ISO 639-1 language code and the redirect_url to the vdm_order function, this will smooth the user-experience in case of cross-domain-cookie/session difficulties. If your site runs PHP it could look like this: