Trouble reformatting code to include methods

Hi need to write this code so that it is broken up into methods correctly and I am lost. The methods I need to use are (as well as the main method etc):

menu()
string_function()
number_function()
create_username()

Here is what I have done, it is almost working code but it wont break up into a more modular state.

package testOne;


import java.io.*;
import java.util.Scanner;
public class MainMenu {

    public static void main(final String[] args) {
        System.out.print("Enter your full name: ");

        final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        String me = null;

        try {
            me = br.readLine();
        } catch (final IOException ioe) {
            System.out.println("Error trying to read your name");
            System.exit(1);
        }

        System.out.println();
        System.out.println("Thank you, " + me +".");
        System.out.println();
        System.out.println ("Please choose from one of the following options:");
        System.out.println();
        System.out.println("1 = create new user");
        System.out.println("2 = do maths");
        System.out.println("3 = exit");

        int choice = 0;
        final Scanner scanchoice = new Scanner(System.in);

        while (choice != 3) {



            System.out.println();
            System.out.println("Enter \"1\", \"2\" or \"3\":");
            choice = scanchoice.nextInt();

            switch (choice) {
            case 1:  create_name();
                     break;
            case 2:  Factorial();
                     break;
            case 3:  System.out.println("Thanks for using this programme");
                     System.exit(0);
                     break;
            default: System.out.println("I am sorry, please enter 1, 2 or 3");
                     break;
            }




        }//WHILE LOOP BRACKET

        scanchoice.close(); 

    }//MAIN METHOD BRACKET

    public static void Factorial() {
        // TODO Auto-generated method stub


        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter the number whose factorial is to be found: ");
        int n = scanner.nextInt();
        int result = factorial(n);
        System.out.println("The factorial of " + n + " is " + result);
        return;
    }

    public static int factorial(int n) {
        int result = 1;
        for (int i = 1; i <= n; i++) {
            result = result * i;
        }
        return result;
    }

    public static void create_name() {
        System.out.print("Enter name: ");

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        String fullName = null; 

        try {  
            fullName = br.readLine();
        } 
        catch (IOException ioe) {  
            System.out.println("Error trying to read your name");
            System.exit(1);
        }

        int spacePos = fullName.indexOf(" ");

        String firstName = fullName.substring(0, 1);
        String secondInitial = fullName.substring(spacePos+1, spacePos+6);
        String userName = firstName.concat(secondInitial);

        System.out.println("Hello.  Your username is " + userName);
    }
}

I really need help here!