adding multiple hooks

I am using Arum theme (Aurum Child) and have a Hook In in the child themes functions.php file

this is the current file code

<?php
/**
 *	Aurum WordPress Theme
 *
 *	Laborator.co
 *	www.laborator.co
 */

add_action('wp_enqueue_scripts', 'enqueue_childtheme_scripts', 1000);

function enqueue_childtheme_scripts()
{
	wp_enqueue_style('aurum-child', get_stylesheet_directory_uri() . '/style.css');
}
function wc_remove_related_products( $args ) {
	return array();
}
add_filter('woocommerce_related_products_args','wc_remove_related_products', 10);
// Hook in
add_filter( 'woocommerce_checkout_fields' , 'custom_override_checkout_fields' );

// Our hooked in function - $fields is passed via the filter!
function custom_override_checkout_fields( $fields ) {
     $fields['shipping']['shipping_phone'] = array(
        'label'     => __('Phone', 'woocommerce'),
    'placeholder'   => _x('Phone', 'placeholder', 'woocommerce'),
    'required'  => false,
    'class'     => array('form-row-wide'),
    'clear'     => true
     );

return $fields;

}

I want to change the placeholder in the Order Notes and from my research I need to add the following

// Hook in
add_filter( ‘woocommerce_checkout_fields’ , ‘custom_override_checkout_fields’ );

// Our hooked in function – $fields is passed via the filter!
function custom_override_checkout_fields( $fields ) {
$fields[‘order’][‘order_comments’][‘placeholder’] = ‘Add gift tag message here';
return $fields;
}

I am unsure of how to combine the two

I have tried several ways and keep getting php errors

any tips ??

https://www.ads-software.com/plugins/woocommerce/