I can't make the ContentPane static but I have to access it In another method that I'm accessing in another class and I keep getting this error:

Cannot make a static reference to the non-static method
    getContentPane() from the type JFrame

..and when I try to setSize

Cannot make a static reference to the non-static method setDefaultCloseOperation(int) from the type JFrame

I am so confused. Can you please help me?

Edit1

ToutrialStart

public class ToutrialStart extends JFrame implements ActionListener
{
static Container contentPane = getContentPane();
public static void schoolDecider()
{
    contentPane.setLayout(null);
    contentPane.setBackground(Color.BLACK);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setSize(1024, 600);
    setLocation(0,0);
    setTitle("Title");
    setResizable(false);
}
}

touDia

public class touDia extends JFrame implements actionListener
{
    public void school()
    {
        ToutrialStart.schoolDecider();
    }
}

You are getting this error because all the methods of JFrame class which you have used here are non-static and you can not make a static reference to the non-static methods. However you can rewrite your code as follow -

public class ToutrialStart extends JFrame implements ActionListener
{
Container contentPane = getContentPane();
public void schoolDecider()
{
    contentPane.setLayout(null);
    contentPane.setBackground(Color.BLACK);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setSize(1024, 600);
    setLocation(0,0);
    setTitle("Title");
    setResizable(false);
}
}
public class touDia extends JFrame implements actionListener
{
    public void school()
    {
        new ToutrialStart().schoolDecider();
    }
}

Also you should avoid extending JFrame. Read this post for further info - Extends JFrame vs. creating it inside the program