create 3 classes clinic, pharmacy, surgery

Hi frenz,
as part of my project, i need to create 3 classes.My problem is i hv clinic class n pharmacy class n surgery class.i must let user to create surgery info tur surgery class n medications info tru pharmacy class n shoud charge a patient wen he checked out frm clinic. can sumone draw me a class design or hw shld i implementing it. Sore im stil new.