It's simple to add the Informizely code snippet to Google Tag Manager. See this FAQ for more information.
If you enable our Google Analytics Integration for your site and also load Google Analytics through Google Tag Manager, you need to make sure that an empty tracker name is specified for the Google Analytics tag in Google Tag Manager.
This is how to do that:
If you don't set an (empty) tracker name, Google Tag Manager generates a random tracker name for Google Analytics events and the Informizely widget has no way of knowing where to send the events.