It’s often hard to get much detailed information on the operations of Chinese industries. Fortunately, the combination of national security concerns and broad interest in airplanes and aircraft manufacturing means there’s a nice swath of government/NGO reports, major media coverage, enthusiast websites, and popular books covering the Chinese aerospace industry. Below is a list of sources I found useful for learning about Chinese commercial aircraft manufacturing. None of them, with the possible exception of “China Airborne," are the sort of things that are good to just pick up and read, unfortunately, but if you want to learn more about Chinese commercial aircraft they’re the place to start.
Sources I found useful (roughly in order of importance)
RAND reports (2001, 2011, 2014, 2017): The think tank RAND has produced several good reports on the progress and prospects of the Chinese aerospace sector. The two best ones are probably Ready for Takeoff: China’s Advancing Aerospace Industry and The Effectiveness of China’s Industrial Policies in Commercial Aviation Manufacturing, and are where I’d start for learning about Chinese commercial aircraft manufacturing. Chinese Investments in US Aviation and The Military Potential of China’s Commercial Technology also have some useful information.