Do I have to click on "Close the contest" first to get the results?

No, you don't have to - This button is independent of the results.

The competition is still open for students who have not managed to participate before 10 June. You therefore have the possibility to close the access to the contest by clicking on the button "Close the contest" in your user account for your school. If there are still some students who would like to participate, you can also go back to "Open the contest" afterwards. 

It may then take one or two hours until you receive access to the contest.