Go to the guard, tell them that you're here for interview. Get a visitor and applicant id, walk to the 4th floor. You leave your bag and phone before entering the interview site. There's a time-limited highschool English exam, a pronunciation test, a simulated call test, and some asynchronous 1 on 1 interview. All of it is computerized. They make you write a review on Glassdoor at the end but you don't have a phone so you can't confirm your sign in to post the review. The interview place was air-conditioned and you'll be guided only by a fast-speaking low-sounding English speaker. If you don't take too long to answer, you can finish it all before 2 hours.