how add administration menu in wordpress

1<?php
2/** Step 2 (from text above). */
3add_action( 'admin_menu', 'my_menu' );
4 
5/** Step 1. */
6function my_menu() {
7    add_options_page(  //this code Add submenu page to the Settings main menu
8        'My Options',
9        'My Menu',       //this paramenter display menu option in administration setting 
10        'manage_options',
11        'my-unique-identifier',
12        'my_options'
13    );
14}
15 
16/** Step 3. */
17function my_options() {
18    if ( !current_user_can( 'manage_options' ) ) {
19        wp_die( __( 'You do not have sufficient permissions to access this page.' ) );
20    }
21    echo 'Here is where I output the HTML for my screen.';
22    echo '</div><pre>';
23}
24?>