How to Hide Modal Window Admin Menus

function plt_hide_modal_window_menus() {
	//Hide the "Wow Plugins" menu.
	remove_menu_page('wow-company');
	//Hide the "Wow Plugins →  Hey" menu.
	remove_submenu_page('wow-company', 'wow-company');
	//Hide the "Wow Plugins → Modal Window" menu.
	remove_submenu_page('wow-company', 'modal-window');
}

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

Where do I put this code?