Going by the Fragrant Harbour forum, I assume this is how it works -
Stage 2 : Aptitude test, Quick Math test, Technical and HR interview, Group exercise, Flight Planning exercise (Boy, we're in for some fun).
Stage 3 : Medical Test, ICAO EPT, Management Interview
Stage 4 : Flight grading.
I read somewhere that a note will be slipped under your hotel room door after the Stage 2 interview. The contents of that note could be :
1. Congratulations, you have been shortlisted for Stage 3, or
2. Sorry, but you have to leave Hong Kong tonight.
One of those reality TV shows.