It is often required to have your customers sign off of on a terms of service before actually processing an order.  Prestashop 1.5 allows this feature in an option simply called TERMS OF SERVICE in the order preferences.  The following tutorial will guide you in how to enable this option and also select the specific terms of service page that will be displayed before an order can be processed.

Require Terms of Service before Processing Orders in Prestashop 1.5

1. Login to the Administration Panel as an Administrator
2. Hover over the menu bar where it says PREFERENCES, and then click on ORDERS in the drop down menu. Select the TEREMS OF SERVICE option per the screenshot below:
   
   
   
   
3. To enable the TERMS OF SERVICE option, select YES or select NO to disable it. 
4. If the option is ENABLED, click on the drop-down menu next to CONDITIONS OF USE CMS PAGE, and select the page that you wish to display.  This page will require that the customer AGREE to the displayed conditions before the order can be processed.
5. Select the green SAVE button  in the top right-hand corner of the screen to save your selections.

The TERMS OF SERVICE option is a great feature to enable so that your customers are made aware of any stated conditions before processing an order in your Prestashop 1.5 shop.  If you need to edit or create a CMS page, please see Editing a CMS Pages in Prestashop 1.5.