How does GoogleTagManager work?

Hello, I have installed your extension and have followed the following tutorial

https://support.weltpixel.com/hc/en-us/articles/115006195028-How-to-solve-compatibility-issues-Google-Tag-Manager-Enhanced-Ecommerce

In GTM debugging the tags do not get fired. For example when I add a product to cart or when I click on the product the tags do not get fired.

So technically how does this extension work? Also previously the ecommerce data with the default magento module was being sent, but now after installing the extension it has stopped being transmitted. 

If we can figure for this module to work well with our website, we will consider buying the pro version.