Create an Account Program Project

I know I'm not supposed to ask for code and that's not what I intend to do. I haven't actually gotten anywhere with this, but I really want to! Can anyone give me parsels of code/tips for doing this? I have a program that opens a JFrame and asks for an account user and password. But how can I connect this and actually make an option for creating an account?
Here is the code for logging in to the account.

import javax.swing.JOptionPane;

public class FrameTest {
	
	public static void main(String args[]) {
	
	String username =
		JOptionPane.showInputDialog("Username:");
	String password =
		JOptionPane.showInputDialog("Password:"); {
	
	if (
		username != null &&
		password != null &&
		(
				(username.equals("bloodfall90") &&
				password.equals("hi"))
		
		)
		)
	{
		JOptionPane.showMessageDialog
			(null, "Correct.");
	} else {
		JOptionPane.showMessageDialog
			(null, "Incorrect.");
	} 
		}
}

}