What is an event?  
An event is an action on your website that isn’t normally tracked by most std analytics systems, such as pdf views, email links and some modern form submission which shows a message rather than another page.

Why are events important?
Your goals shouldn’t be limited to basic transactions, such as, purchase or contact us.  By setting secondary recordable events / actions you can track if prospects ‘view details’ on your product/service, view price lists, watch videos. Which can show as a ‘positive’ response to marketing activities.

How can i implement Events?
Implementation can be done through direct code insertion, tag manager trigger, or settings within your CMS. More info on implementation can be found at Google event tracking.