To configure this click on the Setup drop down > Click Communications.
The communications screen will appear.
The Order Disclaimer box will display a message to the customer at the final check out screen.
The Order Confirmation box will display a message to the customer after they have finalized their order and checked out.
The Order Thank You box will display a thank you message to the customer at the bottom of the confirmation email that will be sent after they submit their order.
When you are satisfied with you messages click the "Next" button at the bottom of the screen to save your changes.