(1) Go to a notary office if the documents should be notarized or tanslated;
(2) Send the documents to the Department of Consular Affairs of the Ministry of Foreign Affairs in China or local Foreign Affairs Office for Consular Authentication;
(3) Send the documents to the embassy or consulates of the concerned country for Consular Legalization.
Or
The Consular Authentication/Legalization may not be requested by the concerned authority in that country.
Please visit http://cs.mfa.gov.cn/zggmcg/lsrz/ for more FAQ.