heio i mega need help here.

this is for uni and I can't wrap my head around this.

i don't understand how I'm supposed to add the null(but as actual strings) values into the addStuddent method from the RegistryTester.

I've checked my entire course's stuff and it doesn't describe how to do it at all and i cant find anything online relating to the topic :<

public class RegistryTester 
{
    public static void main(String[] args) 
    {
        Registry list = new Registry();
        
        list.addStudent();
    }
    
}


import java.util.LinkedList;

public class Registry   
{
    //vars
    LinkedList<student> studentList;

    public Registry()
    {
        studentList = new LinkedList<>();
    }

    public void addStudent(student student)
    {
        studentList.add(new student(null, null, null, null));
    }
    
    public void deleteStudent(String studentID) 
    {

    }
    
    //strings
    public String toString() 
    {
        return getClass().getName() + studentList;
    }
    
    public String format() 
    {
        return "";
    }
}


public class student 
{
    //veriables
    private String forName;
    private String surName;
    private String studentID;
    private String degreeScheme;


    //constructor
    public student(String inFN, String inSN, String inSID, String inDS)
    {
        forName = inFN;
        surName = inSN;
        studentID = inSID;
        degreeScheme = inDS;
    }


    //setters
    public void setForName(String inFN)
    {
        forName = inFN;
    }

    public void setSurName(String inSN)
    {
        surName = inSN;
    }

    public void setStudentID(String inSID)
    {
        studentID = inSID;
    }

    public void setDegreeScheme(String inDS)
    {
        degreeScheme = inDS;
    }


    //getters

    public String getForname()
    {
        return forName;
    }

    public String getSurName()
    {
        return surName;
    }

    public String getStudentID()
    {
        return studentID;
    }

    public String getDegreeScheme()
    {
        return degreeScheme;
    }


    //string and toString

    public String toString()
    {
        return getClass().getName() + "[Forename = " + forName + "  Surname = " + surName + "  Student ID = " + studentID + "  Degree = " + degreeScheme + "]";
    }

    public String format()
    {
        return String.format("%s\t%s\t%s\t%s\t", forName, surName, studentID, degreeScheme);
    }
}

public class student 
{
    //veriables
    private String forName;
    private String surName;
    private String studentID;
    private String degreeScheme;


    //constructor
    public student(String inFN, String inSN, String inSID, String inDS)
    {
        forName = inFN;
        surName = inSN;
        studentID = inSID;
        degreeScheme = inDS;
    }


    //setters
    public void setForName(String inFN)
    {
        forName = inFN;
    }

    public void setSurName(String inSN)
    {
        surName = inSN;
    }

    public void setStudentID(String inSID)
    {
        studentID = inSID;
    }

    public void setDegreeScheme(String inDS)
    {
        degreeScheme = inDS;
    }


    //getters

    public String getForname()
    {
        return forName;
    }

    public String getSurName()
    {
        return surName;
    }

    public String getStudentID()
    {
        return studentID;
    }

    public String getDegreeScheme()
    {
        return degreeScheme;
    }


    //string and toString

    public String toString()
    {
        return getClass().getName() + "[Forename = " + forName + "  Surname = " + surName + "  Student ID = " + studentID + "  Degree = " + degreeScheme + "]";
    }

    public String format()
    {
        return String.format("%s\t%s\t%s\t%s\t", forName, surName, studentID, degreeScheme);
    }
}