For a Student to Graduate, they must study at the campus for the full 3 years and complete their course. In the first campus they study either VR or Scientography. You start the game with 10 students for the 1st year.
As long as you stick to the challenges of reaching 3 stars, try complete all personal goal requests/ assignment requests received in your inbox, you can't really miss it. Your first 10 students should all graduate.
I also made sure my average Grade was above a B at all times. You can see this in the bottom right hand corner. You can also check students individual grades by going on the students tab.