Google Analytics will track the visitors for your website. It's required that you have a Google account in order to use Google Analytics.
Go to the upgrade store and click view upgrades on the SEO and Analytics section.
Search for Google Analytics and click add to site.
Via settings (left sidebar) go to Google Analytics and insert the Google Analytics UA key found in your google account.
Do not forget to publish all pages of your website when you have updated your Google Analytics KEY.