Notarization & Authentication for marriage with a Chinese citizen

I plan to get married with my girl friend from Sichuan, China next year. I need your professional advice because I want to know how the process and what are the supporting documents from my side as well as my girl friend home country before Notarization & Authentication.

Question 1) Do i need to search/extract letter of confirmation of marital status of myself?

Question 2) For the Notarization & Authentication, what is the documents should get from my girl friend side and myself?

Your prompt reply is much appreciated.

Kind regards,
Alfred Chan