As stated in your official admission letter, there is a diagnostic interview (orientation) session which is required for every newly admitted CS master program student. Participating in a diagnostic interview is mandatory, not optional.
The interview will have two sections: The first part is a program introduction/overview along with a policy and requirements discussion. That part is done in a group setting for about 60 - 90 minutes. After that, each student will meet with Dr. Peng individually for background verification/clearance.