The official website doesn't mention anything about the preparation for interview process. But Beginner's class aims to provide essential and basic knowledge about Korean Language. So when you plan to attend the interview, just go through the background of Korean Language. Be prepared for answering why you are interested in learning this language. Also learn a little about South and North Korea and their cultures. Take self attested documents, passport size photographs and Id proof. Also please visit their official website at: http://india.korean-culture.org/en/500/board/397/read/101134 for an idea of the official notification.