Unless the selected payment method is “payment in advance” you don’t need to do anything. The order will automatically be forwarded to Unitedprint. File checks, production, and shippments to your customers will all be handled by Unitedprint. You can track the status of orders in your backend. As soon as an item was shipped, your USS partner shop sends a shipping confirmation mail to your customer including the invoice document.
All of this happens without any involvement on your side. However, since Unitedprint will never directly contact your customers, you should be available for queries of customers or Unitedprint.
In case the selected payment method of an order is “payment in advance”, you need to check whether you have received the payment and release (mark as “Paid”) the individual order items. Only then the items will be forwarded for production.