swing - Adding a JPanel into a JFrame

I know this sounds like an easy question, but I am making a simple text adventure with buttons and such, and I cant figure out how to add my Jpanel into my JFrame. My JPanel has a bunch of buttons and graphics and stuff if that makes a difference. I have provided the code below. frame panel=new frame(); is the other class which extends JPanel. I know its confusing that its called "frame", its because I used to have it extend JFrame. Anyways my code doesnt produce the buttons, graphics etc, from the other class like it should. Thanks,

package sonomaroller;

import javax.swing.*;
import java.awt.*;
import static javax.swing.JFrame.*;


public class SonomaRoller extends JFrame {

    public static Dimension size = new Dimension(550,550); //Dimension of Frame
    public static String title = "Sonoma Roller v0.00" ;


    public SonomaRoller(){

      setTitle(title);
        setSize(size);

        setResizable(false);
        setLocationRelativeTo(null); // null centers window on screen
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        System.out.println("hello?");  
        //setLayout(null); 
        setVisible(true);

    }



   public static void main(String[] args) {

       SonomaRoller object1=new SonomaRoller();   
       frame panel=new frame();


    }
}