You should be on the side of the tram tracks further away from the ETH main building. You can either buy a single ticket valid for 1 hour or a day ticket valid for 24 hours. Since the day ticket is only twice the cost of the single ticket, it is often more economical to buy the day ticket. There are several different ways of choosing the day ticket on the ticket machine. The ticket machines accept only coins unfortunately.
Tickets have to be bought before boarding since no tickets are sold on trams or buses.
Tram 9 and 10 runs every 7 to 8 minutes during the day. The Bus 69 bus stop is on the same platform that you exit onto at Bucheggplatz. There is a great view of Zurich city along Bus 69 route on the left side of the bus. You can even see the Alps on a clear day. Bus 69 runs every 7 to 8 minutes during the day.