Your camper is equipped with an manual parking brake. To use the parking brake, push the pedal on the left side of the drivers area:
When the parking brake lights up yellow it is set. If you try to start driving with the parking break set a sound goes on to let you know that you need to release it first.
Release it if you want to start driving again by pulling the release handle.
We recommend using it even when parked on a flat surface as the vehicle sometimes rolls when you are walking around the van.
Watch this video for a more detailed explanation: