Installing Google Analytics in your website
Go to Google Analytics > Admin > Tracking Info > Tracking Code and get the tracking Code (GATC).
Example code:
<script>
(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-11111111-1', 'auto');
ga('send', 'pageview');
</script>
Install the tracking code in your website, between <head></head>
tags, in every page you want to track.
To do this you should access your website source code or contact with your webmaster.
Alternatively you can install Google Analytics via Google Tag Manager. I personally recommend it that way because it will save you a lot of time in the future :)