Go to Jungammanova Street. Look for blue square name plate which says 25.
How to reach Jungammanova? Its closest to Wenceslas Square. If you are staying father away, take metro to station Mustek A or Mustek B. Its only 3 minutes walk from the metro station.
Once you reach the gate of 25 Jungammanova Street, call on mobile +420 722 708 257. Tbey will open the gate & its your entrance to heaven. I have been there twice & its great.