Find lots of things to do (be it cultural, a visit to a luxury sauna or some reading at the most stylish library of the city) and the most beautiful spots of Helsinki on the city's tourist board's website: https://www.myhelsinki.fi/en/see-and-do/sights
Our colleagues from CFCI have made a selection of Weblinks that may help you have an even more interesting and good time while in Helsinki. Why not add a couple of days for exploring the city and its surroundings?
The city of Helsinki
Public transportation in the metropolitan area
In case you want to brush up on the cultural idiosyncrasies, tclimatic phenomenons and find tips to discover our Northern neighbour, Finland, the country's tourist board has put together lots of information and tips: https://www.visitfinland.com/