On the street side, you can recognize the driveway to the site by the totem with the established businesses.
You drive up the driveway between the trees until you reach the barrier.
There, ring the bell (next to te blue arrow) and let the doorman know that you are coming for Openbare-verkopen.be. They will open the barrier for you.
Then take the 1st street to the right (there is also a sign) until the end. In front of you you will see building B1.