Connex for QuickBooks can sync orders from all versions of QuickBooks Desktop, including Pro, Premier, Enterprise and Wholesale, into ShipStation. Here are the steps:
1. Set-up a scheduled task with Connex for QuickBooks
2. Turn on QuickBooks class tracking
3. Create some new invoices or sales receipts in QuickBooks
4. Ensure these transactions are formatted properly, with a class of ShipStation on each order
This video demonstrates these steps.
For more information read this KB: Sync QuickBooks Online to ShipStation