short excert in featured products

I have search in find out to to add excerpt to WC product and how to limit it to frontpage product alone, also i see a recommedation in the use of is_featured() here

But i dont understand how to use it, kindly help pls, below is my code

add_action( 'woocommerce_after_shop_loop_item_title', 'ins_woocommerce_product_excerpt', 35, 2);
if (!function_exists('ins_woocommerce_product_excerpt')){
	function ins_woocommerce_product_excerpt(){
		if(is_featured()){
			if ( is_front_page() ) {
				echo '<span class="excerpt">';
				echo substr(get_the_excerpt(),0,115);
				echo '</span>';
			}
		}
	}
}