Tram lines 4 and 15 will take you to the Rudolf Brun Brücke stop, from where you can walk uphill along Graue Gasse in the direction of the University / ETH to Hirschenplatz-Square. And you will already spot the PLATZHIRSCH on your left.
Your bonus: If you arrive by train, we will give you the ZVV day pass with which you can travel free of charge on the public transport system in the city.