Its an Uni project..
Good guess on my part since its extremely unlikely that it'd be a professional question like that.
Assuming you already know the basics of database design from you uni course, I'd start with looking at the people entities (patients, doctors, nurses etc) and their records then build from there. As you will already know, an employee can become a patient so I would suggest a single table (or group of tables) for people/persons and go from there. At least thats how I would do it.
As it is a uni task I'd suggest other comments simply point you in the right direction rather than giving you a direct answer since you will learn more and everybody will have slightly different approaches. You will gain more by doing it yourself and your teacher will learn more from your approach