Payment depends on whether an order has checked out for by credit card or offline.
If you have set up credit card payments, and an order is paid by credit card, the final amount of that order (the order total less the service fee and any credits approved by you) will be deposited into your bank account 1-2 business days after the credit window closes.
Note that if there are multiple orders paid with a credit card per day, those orders will be paid into your bank account in a batch. You can see the details of which orders are included in each batch by clicking on the "Batch Payouts Summary" grey button on the Financials link in the main navigation header.
If you set up terms with specific buyers (only available on the Unlimited Plan type), you will need to collect from those buyers offline. If you have automatic emailing of invoices enabled on your Tools & Settings page, invoices will be sent to buyers automatically after the credit window closes, and those invoices will have your farm name and mailing address where checks should be sent. If you have automatic emailing of invoices disabled, you will need to send the buyers invoices manually.
Make sure you mark each order as paid when you receive payment by going to the Financials link and clicking on the "Mark as Paid" green button. That will also make the order display as "Paid" in your buyer's account.