Working inside a former aircraft hangar, the competition organisers spread 200 tons of lava rock across an area equivalent to seven tennis courts, landscaping it into a Moon-like environment, including the main crater of interest. Then they scattered rocks, including a hundred larger simulated boulders larger than a metre across, whose positions were precisely geo-referenced.
These measurements served as the basis of map provided by ESA to the rover teams. The idea was to give them the equivalent level of local information they would get from satellite imagery in a 'real' mission, while still leaving smaller-scale surprises. Once complete, the moonscape was kept concealed from the rover groups behind black curtains, so they would see it only through the cameras on their rovers. The 13 teams each made their prospecting attempt one at a time.