Main method cannot be found

i'm completely new to java, i am reading this java book for my introduction to programming course and i'm only on chapter 3 (week 3 of class) I'm using jGRASP and when i compile it can't find my main method and when i put in the public static void main(String[] args), I get a bunch of errors in my public and private areas.

import java.util.*;
class Checkup
{  
   private int patNum; //Patient Number
   private int systolic; // Systolic blood pressure
   private int diastolic; // Diastolic blood pressure
   private int LDL; // LDL cholesteral 
   private int HDL; // HDL cholesteral

   // START patNum set and get.  
   public void setpatNum(int Num)
   {
      patNum = Num;
   }
   public int getpatNum()
   {
      return patNum;
   }
   // START systolic set and get.
   public void setsystolic(int sys)
   {
      systolic = sys;
   }
   public int getsystolic()
   {
      return systolic;
   }
   //START diastolic set and get
   public void setdiastolic(int dia)
   {
      diastolic = dia;
   }
   public int getdiastolic()
   {
      return diastolic;
   }
      //START diastolic set and get
   public void setLDL(int Lchol)
   {
      LDL = Lchol;
   }
   public int getLDL()
   {
      return LDL;
   }
}