order-created-hook.php

<?php

add_action("surecart/order_created", function( $order ) { 
  $checkout = \SureCart\Models\Checkout::with([
    'line_items',
    'line_item.price',
    'line_item.fees',
    'price.product',
    'discount',
    'discount.promotion',
    'shipping_address',
  ])->find( $order->checkout );
  
  // do something with the checkout.
});