The metro station Slussen is located just next to the hotel. All trains of the green and red lines stop at Slussen, and the blue line departs from T-central.   
 
Several city buses and buses to Nacka/Värmdö depart from Slussen. Find your best trip at SL.se. 
 
You can easily buy tickets for the subway and buses in the SL app, at the subway kiosks, Pressbyrån, or 7-Eleven.