There's quite a bit of literature and media relating to Dr. Yan Xin published before the turn of the millennium. However, I think the YXQ group is restricting their publication and distribution, which is why videos of Dr. Yan Xin are being taken down. I'm not sure why, I haven't been very active.
A good book which is relatively easy to find online in PDF form is "Secrets and Benefis of Internal Qigong Cultivation". I can't find my copy right now but I believe it has the nine steps in it.