From all the major cities such as Gothenburg, Stockholm, Copenhagen or Oslo you can go by train or bus to Karlstad. Search on Google Maps to get an overview from your starting point to Torsby. Then you can choose an option and buy your ticket at SJ (train), Flixbus or Bus4you.
You are able to go both by train or bus to Torsby from Karlstad. Search for departures and timetables at Värmlandstrafik. How to reach the meeting point for your canoe tour at the Motor museum ("Fordonsmuseum") from the train station is described in detail in your travel documents, or check this link: Fordonsmuseum
If you are driving to Torsby, the easiest way is to go by road E45. To find your direction, look for example on Google Maps from your starting position to Torsby. The meeting point for your canoe tour is Torsby Motor Museum (Torsby fordonsmuseum), which you reach by turning left just before you are in the centre of Torsby. Here are links with directions from some cities: Stockholm, Gothenburg, Oslo, Copenhagen