The displayer is one of the 2 main parts of a customizer. It's entire purpose is to render the customized product with the current configuration so that your clients can see how the product looks like. It is important to make your product look as good and marketable as possible to increase conversion.
The Question Panel is the other main part of a customizer. Every action your clients will take towards creating their design will be made through the Question Panel.
The Add to Cart is the final action your customer will take in his customization process. It does 3 things, first it saves the customer's design to our database, then it adds the design to the customer's cart and finally, it redirects him to the cart page.
The Displayer Controls are a set of tools the customer can use to change what the displayer renders. He can change the current view of the product by clicking on the view dots or use the view arrows. He can also use the zoom in/zoom out buttons to enlarge the product in the displayer.