You can view where customer traffic is coming from by going into your stats section. While in stats you will want to select which event this is going to be for. After this, go to the Marketing tab and you will see a few different sources of traffic: Tracking Codes and Traffic Source.
Tracking codes are codes that you have set previously. These show the traffic and sales being generated by the links you created. These are great because you see all the traffic coming from an Ad using the tracking code or you can see how successful one of your promoters are with their tracking code.
Traffic source information is automatically populated from people coming to the site. This will show how people got to your event page such as a Google search or maybe another part of the site.