In your Website press Events and get the detailed explanation on how to use it pressing <>.
Basically you need to add the pa.track() JavaScript function and you can use name, value and unit keys (more coming in future releases).
Example code for tracking registers – using a link:
<a href="https://mydomain.com/register" target="_blank" onclick="pa.track({'name' : 'Register from banner'})">TRY FREE</a>
And here you have an example code – using button:
<button onclick="pa.track({'name' : 'Register button'})">Buttonname</button>
Google Tag Manager
If you want to use Google Tag Manager, follow this guide.