First I made a new folder "CEDICT.dictionary" in /Library/Dictionaries
Next I unzipped the download and put the resulting folder "Contents" into the CEDICT.dictionary folder I just created. Then it shows up and works fine in Dictionary.app
I am very pleased with CEDICT. I strongly recommend it.
CEDICT for Apple Dictionary
chinese to english, pinyin pronunciation & voice soundset
Version: 1.2