My only confusion is:
Full code before Adding google tag manager as below ()
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','//www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-65833292-1', 'auto');
ga('send', 'pageview');
Now, for google tag manager code to be added, do I need to add the google tag manager script in addition of the above code or should I remove the tracking code of analytics and add ONLY GTM snippet?