How to Hide Wordpress Pretty Testimonial Admin Menus

function plt_hide_pretty_testimonial_menus() {
	//Hide "Settings → Pretty Testimonial Options".
	remove_submenu_page('options-general.php', 'pretty-testimonial-settings');

	//Hide "Pretty Testimonial".
	remove_menu_page('edit.php?post_type=testimonial-items');
	//Hide "Pretty Testimonial → Pretty Testimonial".
	remove_submenu_page('edit.php?post_type=testimonial-items', 'edit.php?post_type=testimonial-items');
	//Hide "Pretty Testimonial → Add New Pretty Testimonial".
	remove_submenu_page('edit.php?post_type=testimonial-items', 'post-new.php?post_type=testimonial-items');
	//Hide "Pretty Testimonial → Testimonial Category".
	remove_submenu_page('edit.php?post_type=testimonial-items', 'edit-tags.php?taxonomy=testimonial_cat&post_type=testimonial-items');
}

add_action('admin_menu', 'plt_hide_pretty_testimonial_menus', 11);

Where do I put this code?