No special access issues
Park by the road following the usual laws and rules. There is a 2h free parking area nearby.
The metro stop of Herttoniemi is the nearest but the one for Kulosaari is not far either.
Easiest way down is on the left side of the fence (looking from above). There is a via ferrata with a chain for safer access up and down. The access is suitable for those who can climb but is probably a bit too much if you're afraid of heights. Harness and a short lanyard will make the approach more safe.