Hi, Koen and David
Because of requests from some contributors, I just temporarily created one page at http://docs.moodle.org/20/en/Translation_Guide_for_Chinese_Contributors. And also I add a link to it at http://docs.moodle.org/20/en/Translation
When there is an official way to do such things, I'll be happy to migrate it.
If I break some rules, feel free to correct me. Thank you.