Timetable booklets are free of charge and you can pick them up at train stations or onboard the bus, as well as at the SL Centers.
SL Center is a travel information center that is located around the town.
You can download a timetable at the Swedish section, but that service is not available in English.
The timetables are in Swedish, but should be fairly easy to understand if you have a slight command of Swedish.
The easiest way to plan your journey, however, is to use the planning tools here on the homepage. Choose between real time departures if you are on the go now, or scheduled departures if you want to plan ahead.