Take the highway exit St.Gallen/Kreuzbleiche and drive towards the center. Out of the tunnel, change to the left lane and follow the signs towards the university.
By public transport:
There are direct train connections to St.Gallen every half hour from Zurich main station as well as Zurich airport. The journey time is about 1 hour. There are also direct express trains from Bern (2 hours), Geneva (4 hours) and Munich (3 hours) to St.Gallen. At St.Gallen main station, take bus line 5 in the direction of Rotmonten. Buses run every 10 minutes. Get off at the bus stop Universität and cross the main street. Alternatively, walk to the bus stop Bahnhof Nord (back of the train station) and take bus number 9 to Universität West.
Zurich Airport is only one hour away from St.Gallen by car or train. There is a direct train from the airport to St.Gallen twice an hour. The airport St.Gallen-Altenrhein is located 10 minutes from Rorschach and 30 minutes from St.Gallen.