If you have not already signed up for BDOW! (formerly Sumo), check out the Getting Started with BDOW! Guide before following the instructions below.
Installing BDOW! on Prestashop
Open the folder where your PrestaShop website's files are located (NOTE: Your screen may look different).
Navigate to the themes folder.
Find the folder of the theme you are using with PrestaShop (by default this is set to default-bootstrap).
Open index.tpl in your favorite IDE (code editor).
Paste the Sumo code inside of the head tags within index.tpl (make sure that the code is in between the two body tags), then Save.
Login to your PrestaShop Dashboard and hover over Advanced Parameters in the menu on the left and click Performance (NOTE: In older versions of PrestaShop you must go to the Preferences tab and Performance sub-tab).
Select the option Force Compilation. Then set "Cache" to No. Click Save.
Congrats, you're all done! Go to your PrestaShop website, navigate to the top right corner of the page, and enter your Sumo credentials to start using Sumo! (NOTE: Your website must be deployed to a server for you to see Sumo.)