You (the participants) thoroughly read this manual.
Participant 1 takes object 3 out of the depot and places it somewhere in the exhibition space.
Take the red ropes (with the hook and eye) and mark the location with said ropes.
You discuss the chosen location with your fellow participant. (Why did participant 1 choose this specific spot?)
Participant 2 can choose whether or not to change the location of object 3. If participant 2 chooses to change the location of object 3: you discuss this new location.
You return object 3 to its rightful place in the depot once you’re done.