There are no live auditions. You do the audition by sending a recent DVD with a live-recording, or you can refer to live-video recordings (e.g. Youtube) on the internet in your application account.
You will find all details in the page Application and fees in this Summer Academy section.
If you were accepted for the 2016 or 2017 Summer Academy there is no need for you to do an audition for the SA 2018. Of course you have to commit your application in your application account, but within the application pages you may skip the audition part.