Step 1: Go to https://analytics.google.com to setup an account. (You will need to have a Google analytics account or create one now.)
Step 2: Click on Admin in the lower left corner.
Step 3: Click on Tracking Info in the second column.
Step 4: Copy the full code paragraph as shown below.
Step 5: Open the site builder and click the pencil icon.
Step 6: Click on the hamburger menu in the upper- right corner and click Site Settings.
Step 7: Copy/paste the Google Analytics Code.
Save your changes in the site settings. Then save and publish your site.
Learn more about Google Analytics here.