How to Hide CustomTables Admin Menus

function plt_hide_customtables_menus() {
	//Hide "Custom Tables".
	remove_menu_page('customtables');
	//Hide "Custom Tables → Dashboard".
	remove_submenu_page('customtables', 'customtables');
	//Hide "Custom Tables → Tables".
	remove_submenu_page('customtables', 'customtables-tables');
	//Hide "Custom Tables → Layouts".
	remove_submenu_page('customtables', 'customtables-layouts');
	//Hide "Custom Tables → Import Tables".
	remove_submenu_page('customtables', 'customtables-import-tables');
	//Hide "Custom Tables → Database Schema".
	remove_submenu_page('customtables', 'customtables-schema');
	//Hide "Custom Tables → Documentation".
	remove_submenu_page('customtables', 'customtables-documentation');
	//Hide "Custom Tables → Settings".
	remove_submenu_page('customtables', 'customtables-settings');
}

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

Where do I put this code?