At the first group interview, the recruitment team will observe you, how you interact in a group, if you're friendly, nice attitude, and easy to talk to. They will first do an introduction of the company, flight attendant life, benefits and salary. After the introduction, they will divide into small groups of 5-7. Groups will take turn to do interview (about you, why you want to be FA...), language test (very easy, they talk to you in your language and make you read a small paragraph), and reach test (able to reach a sticky note on the wall, you can tiptoe).
Second interview is one on one with more questions about your experience, your future goals, customer service... (do your research and you'll be fine)
After you pass the second interview, they will schedule you to do health and drug test (very strict) and computer test (which if you fail, you can retake it).
Overall process took about 3 weeks. It wasn't that hard.