Adding submenu to custom plugin menu page created with add_menu_page() function

I have created a custom menu page using add_menu_page() function. Everything in that page appears as it should in the screen. What I am trying to achieve is adding another submenu under the under the page i previously created(i want it to appear just like when you click on the settings menu in wordpress dashboard). I am pasting a code snippet below:

    //creating the menu item for the plugin
function qpv_custom_menu_link() {
    add_menu_page(
        'Quick Product View Options',
        'Quick Product View',
        'manage_options',
        'qpv-options',
        'qpv_options_page',
        '',
        '100'
    );
    add_submenu_page(
        'qpv-options',
        'Quick Product View Appearance',
        'Quick Product View Appearance Settings',
        'manage-options',
        'qpva-options',
        'qpva_options_page'
    );


}

add_action( 'admin_menu', 'qpv_custom_menu_link' );


//creating the submenu page settings
function qpva_options_page(){

    ob_start(); ?

    h2Hello/h2


    ?php
    echo ob_get_clean();
}

I have also checked the wordpress codex and have followed the given instructions, but my problem remains and the submenu page still does not show up in under the plugin name.