Any hints on where I can find what is included in Google Tag Manager Editor Extension, and how to use it? The help documents and SuiteAnswers are circuitously unhelpful.

I agree that the documentation is confusing. It's like just leaving a clue on how you are going to do things but you have to find it on your own way.

These might help you to some extent: • https://netsuite.custhelp.com/app/answers/detail/a_id/27703 • https://www.fourthwc.com/netsuite/2014/02/installing-google-analytics-universal-netsuite-websites.html • https://www.freshegg.co.uk/analytics/how-to-set-up-e-commerce-tracking-in-universal-analytics