To Connect QuickBooks:
1. Go to My -> Settings;
2. Click Connect and login to your Quickbooks account
3. Open the new tab in your settings > QB Accounts
4. Select from what date data should be synced to QuickBooks
Select what status will trigger the sync: Delivered, Invoiced, Paid for both order and job
Select accounts that were imported from yoru QB account and link them to the right ones. 