Suman You have two direct trains from Zurich Airport to Bern every hour, in Bern you can take a local train to Bern Bümpliz Nord and walk to the Mühledorfstrasse 28.
Search the timetable on sbb.ch and you will find the price of the ticket. Be sure to buy a point-to-point, adult ticket if you are 16 years old or older (no supersaver ticket, no half fare). It is valid until the following day at 5 am in every train. You can also buy this ticket at the airport after you arrival (ticket office or vending machines).
If you come to Switzerland to study and stay a long time, and you want to make other trips later, you could buy a Half Fare Travelcard or a Half Fare Travelcard for Youth (under 25 yo).
https://sbb-tickets.cc/en/tickets-offers/travelcards/half-fare-travelcard.html