You can submit a manual order by navigating to Orders → Create order in your Printify account. Then choose from your already created products and proceed to input the delivery address.
Once you reach the last step in the ordering process, you will have the following options:
Fulfill — send the order to production immediately.
Save for later — send the order to production at a later time, according to your Order Approval Settings (the default option is Automatically in 24 hours).