Hi,
Apologize for the reply late.
You can use child theme, and add code to file wp-content/themes/yolo-sofani-child/functions.php
function add_custom_notice(){
echo '
Due to the nature of the medium (metal) each piece has burnishing and shading in different areas of the piece. Click *here* to view a video clip of our art in motion. If you’d like photographs of your exact piece prior to shipping, please utilize the contact form before placing your order.
';
}
add_action( 'woocommerce_before_single_product', 'add_custom_notice', 10 );
You can custom with your code in function add_custom_notice.
Best regard,
James.