Shopify blocks the use of TrackDuck extension due to their Content Security Policy. To install TrackDuck to your Shopify website you’ll need to:

1.  Copy your TrackDuck JavaScript code snippet from your Project Settings>Installation.

Note that all TrackDuck projects have an unique code.

2. You need to take this code and add it to one of your Shopify theme elements that is persistent throughout all of your pages. The most usual case is a theme header file.  Paste the code at the top of the file and save it. Here’s a short video how to do that: