You therefore need a way of tracking what is going on.
First, let's have a quick look at what is going on with the Analytics code.
Once you have created your property, you are told to add a code snippet to your pages:
(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','https://www.google-analytics.com/analytics.js','ga');
ga('create','UA-12345678-90','auto');
ga('send','pageview');