Go to the above coordinates.
You will be in front of a webcam that takes a picture.
Now you need someone to save the picture of yourself taken by the webcam or save it as a screenshot on your smartphone.
To log this cache, you have to post this picture.
Choose "Baan 06" and click on the button "Kies positie"
Wait for a view seconds and refresh the page
(sometimes you have to wait for the button to appear)
The picture should allow to identify you as a geocacher.
How you do that is up to you, if you want:
holding up an umbrella, banners, warning vests, balloons, headlights, or cheering into the camera... be creative!