How to Hide Activity Guard Admin Menus

function plt_hide_notifier_to_slack_menus() {
	//Hide "Notifier".
	remove_menu_page('notifier-to-slack');
	//Hide "Notifier → 📶 Dashboard".
	remove_submenu_page('notifier-to-slack', 'admin.php?page=notifier-to-slack#/');
	//Hide "Notifier → 📑 Activity Log".
	remove_submenu_page('notifier-to-slack', 'admin.php?page=notifier-to-slack#/log');
	//Hide "Notifier → 🧑🏻‍💻 Author".
	remove_submenu_page('notifier-to-slack', 'admin.php?page=notifier-to-slack#/author');
	//Hide "Notifier → ⚙️ Configuration".
	remove_submenu_page('notifier-to-slack', 'admin.php?page=notifier-to-slack#/settings');
	//Hide "Notifier → ▶️ Get started".
	remove_submenu_page('notifier-to-slack', 'admin.php?page=notifier-to-slack#/doc');
	//Hide "Notifier → Upgrade".
	remove_submenu_page('notifier-to-slack', 'notifier-to-slack-pricing');
}

add_action('admin_menu', 'plt_hide_notifier_to_slack_menus', 1000000000);

Where do I put this code?