From Prag`s center by subway or tram to subway station Andel. There you can take a train #4, #7, #9 or #10 from Andel to "U Zvonu". Walk across Mahenova st. to Holeckova st.
From Wenzel sq.: Take a tram #9 or #58 (at night) to "U Zvonu". During a day or night it can not take more than 15 minutes.