It entails writing the Performance "A" exam, Air Law, and a human factors exam. Plan on a couple of months of heavy book work to study for the exams. If you're not familiar with "negative marking" you're in for a treat...
Here is the CAD website:
http://www.info.gov.hk/cad/english/main.htm
For application or enquiry, you can write to:
Personnel Licensing Office
Flight Standards and Airworthiness Division
Civil Aviation Department
10/F Commercial Building
Airport Freight Forwarding Centre
2 Chun Wan Road
Lantau
Hong Kong
Telephone:___ (852) 2769 8653
Fax:___________ (852) 2329 8595