The World's Fastest and Most User-friendly SEO Content Management System | Building & Branding Custom Websites that Get Results
 

It's a simple tag you can add to links.

onclick="ga('send', 'event', 'Mobile Button', 'click', 'Contact');"

The two things highlighted in yellow are the things you can customize. The first is the event category and the second is the event label.

So the full link for the mobile button would look like this:

<a class="btn btn-block btn-primary" href="/contact" onclick="ga('send', 'event', 'Mobile Button', 'click', 'Contact');">Contact Us</a>

Building & Branding Websites that Get Results

The world's fastest and most SEO friendly website code.