It took me some hours (!!) to figure it out and I'm not sure how I did it.
You don't need to fill anything. I used the kuaipan link.
You see two "download" links. A green one left and another one right.
However there is in the above line (建议先保存到快盘再下载，可防止文件过期、分享者取消分享。) a small blue hyperlink.
Click there. Then you get a pop-up, click the blue button and the download will start automatically. In my case it was extremely slow, so you will have to wait.
I hope I helped you.
I must say I'm disappointed by the new Duokan. I have the exact same opinion as buddha2012 had in
this post.
For me Duokan in my K3 had become the primary OS. I used it for all the unsupported files (like epub) and in the end I even used it for the mobis.
However this Duokan2012 for K4NT, although more "polished" looks really ugly for reading. The contrast is really awful and the letters look like when you print something with your printer and the ink level is low.
From what I saw in the chinese forums (google translated it while trying to figure out how I can download it) there are people complaining about that. I really hope they can improve it, because for me it looks way too bad to use it.