I do not need all of the menu products and want some custom menu products to be included the left menu of admin section of Wordpress. Can there be any function I'm able to use to get this done particularly.

Add this towards the functions.php file:

add_action('admin_menu', 'remove_menus');
function remove_menus () {

    //remove pages
    remove_menu_page('edit.php'); //posts
    remove_menu_page('link-manager.php'); //links
    remove_menu_page('edit-comments.php'); //comments

    //add pages
    add_menu_page('New Page Title', 'New Title in Menu', 'administrator', 'new_page_title', 'f_new_page', $icon_url, 31);
    function f_new_page() { include(get_template_directory_uri() . '/new_page.php';
}

More information on getting rid of: http://codex.wordpress.org/Function_Reference/remove_menu_page

Too give a new menu page, browse the following to have an explanation around the variables: http://codex.wordpress.org/Function_Reference/add_menu_page

Place this code inside your styles function.php file and personalize since you need

/* Remove unnecessary menu items from admin */
function remove_menus () 
{
    global $menu;

    //$restricted = array(
    //  __('Dashboard'), 
    //  __('Posts'), 
    //  __('Media'), 
    //  __('Links'), 
    //  __('Pages'), 
    //  __('Appearance'), 
    //  __('Tools'), 
    //  __('Users'), 
    //  __('Settings'), 
    //  __('Comments'), 
    //  __('Plugins'));

    $restricted = array(__('Links'),__('Media'),__('Appearance'),__('Tools'),__('Posts'));
    end ($menu);
    while (prev($menu)) {
        $value = explode(' ',$menu[key($menu)][0]);
        if(in_array($value[0] != NULL ? $value[0] : "" , $restricted)){unset($menu[key($menu)]);}
    }

    remove_submenu_page('edit.php','edit.php');
    remove_submenu_page('edit.php','post-new.php');
    remove_submenu_page('index.php','update-core.php');
}
add_action('admin_menu', 'remove_menus');