How to Hide Arrivala - Online Business Reviews Admin Menus

function plt_hide_arrivala_online_business_reviews_menus() {
	//Hide "Arrivala Reviews".
	remove_menu_page('arrivala_fields');

	//Hide "Custom Fields".
	remove_menu_page('edit.php?post_type=acf-field-group');
	//Hide "Custom Fields → Field Groups".
	remove_submenu_page('edit.php?post_type=acf-field-group', 'edit.php?post_type=acf-field-group');
	//Hide "Custom Fields → Add New".
	remove_submenu_page('edit.php?post_type=acf-field-group', 'post-new.php?post_type=acf-field-group');
	//Hide "Custom Fields → Tools".
	remove_submenu_page('edit.php?post_type=acf-field-group', 'acf-tools');
}

add_action('admin_menu', 'plt_hide_arrivala_online_business_reviews_menus', 21);

Where do I put this code?