CAAC ATP Written
First the medical..I can not help you there, as our company arranges them all, and they are mysterious...It is done in a special hospital, and not by an approved doctor..Maybe contact the medical department of one of the airlines.. Cathay has English speaking doctors on staff who might know how things work on the mainland.
Now, the exam.. Do a search. There is an excellent thread on it. The procedure for study is to memorize the questions and answers. There are links on the other thread to a place in Beijing that sells the q&A book.
Questions sometimes are in Chinglish, Chinese, or completely above understanding, so the Q&A book is a necessity.
People also said study the GLIEM manuals. Never found them that helpful, but if you do not have an FAA license brush up on the 135/121/91/61 FAR's.
Airspace and some of the rules are definitely different in China.
Again, I have no idea how you can do this personally. Maybe contact the CAAC in Beijing and ask (medical too, while you are at it.)
There are some flight schools that can do the prep work...Very, very expensive, and very limited English speaking ability at most of them...very limited...
Good luck on doing it yourself...This is not north america or europe.