The competition is arranged at Hellasgården in Nacka. Hellasgården is a nature reserve 15 minutes by buss from Slussen in Stockholm centre. https://www.nacka.se/boende-miljo/natur-och-parker/natur–och-friluftsomraden/nackareservatet/
Bus 401 goes from Slussen to dwelling several times an hour. The bus stop is called Hellasgården And the journey time is about 15 minutes from Slussen. Check when the bus goes with SL’s journey planner. https://sl.se/
If you go by car it takes about 10 minutes from Gullmarsplan. You go to the dwelling, by Sickla follow Road 260. When you arrive, you will find a large paid car park on your left side.