How to make UIPageViewController work when turning to landscape?

In this tutorial on the UIPageViewController (there is a download for the project below), the author sets an excellent UIPageViewControllerone that works flawlessly in portrait mode.

But when you turn into the landscape, he completely goes crazy. The image is placed in the lower left corner, and in general it is just completely messed up.

I cannot figure out how to solve this problem. I searched and searched, and not a single example of projects works in the landscape. What do I need to do to make it work in the landscape?