Several buses depart from Slussen depending on when you want to go. Please visit www.sl.se for timetable. Take specified bus to Orminge Centre where you will need to change to bus 417 towards Hasseludden. Get off at the stop Hamndalsvägen. The bus trip takes about 35 minutes. From the bus stop it is about a 5-10 minute walk.
See timetable on https://sl.se/en