我正在学习插件开发，需要创建一个包含以下内容的插件：

在WordPress的管理面板中添加菜单项和页面在该页面上，让我们使用具有文本区域和按钮的表单添加文本消息

<?php
/*
Plugin Name: The Admin Messages
Plugin URI: https://wpsaints.com
Author: Wp saints
Author URI: https://wpsaints.com
Version: 9.0
*/

function the_admin_menu() {
    add_menu_page( \'Form\', \'Form Items\', \'manage_options\', \'mypage\', \'the_admin_menu_page\', \' dashicons-menu\', 6 );
    
}

add_action( \'admin_menu\', \'the_admin_menu\' );


function the_admin_menu_page() {
    
    ?>
    <form method="post">
        <br><br>
        <lable><b>Enter your Message</b></lable>
        <br><br>
        <textarea></textarea><br><br>
        <button> Submit</button>


    </form>
    
    <?php
    
    function jal_install() {
        global $wpdb;
        
        $table_name = $wpdb->giftmix . "messagebox";
    }
    
    global $wpdb;
    
    $charset_collate = $wpdb->get_charset_collate();
    
    $sql = "CREATE TABLE $entermessage (
      id mediumint(9) NOT NULL AUTO_INCREMENT,
      time datetime DEFAULT \'0000-00-00 00:00:00\' NOT NULL,
      name tinytext NOT NULL,
      text text NOT NULL,
      url varchar(55) DEFAULT \'\' NOT NULL,
      PRIMARY KEY  (id)
    ) $charset_collate;";
    
    require_once( ABSPATH . \'wp-admin/includes/upgrade.php\' );
    dbDelta( $sql );
    if ( $_SERVER[ \'REQUEST_METHOD\' ] == "POST" ) {
        
        
        $Enter = ( $_POST[ "YourName" ] );
        $Email = ( $_POST[ "Email" ] );
    }
}