Just as few simple question not a formal interview revise your CV and prepare intro are good enough. Be confident and speak Cantonese for the whole process good luck

The form of interview is group based (around 8 people). Everyone is first doing self-introduction one by one. Then, there was a written test which require you to choose the most suitable person among the interviewee to fit in a position like project manager, engineer... and give reasons based on their self-introduction. And finally there was a group discussion. 4 people in a team to brainstorm a solution on a topic and present it to the interviewers.