Also, if you like cycling, Helsinki has a nice bicycle-sharing system and okay cycling roads. There are a lot of stations in the central Helsinki and one is right next to the event venue. There's more information here: https://kaupunkipyorat.hsl.fi/en

It should be easy to get to venue via public transport from the very central Helsinki. The connections from the Kallio region (where I live and where there are apparently plenty of AirBnB flats 😛) are not as good (you have to walk a bit) but still okay. You can check with https://www.reittiopas.fi or with Google Maps public transport directions. @andrea.crotti