please always use English as language inside the forum - thanks!
A page cannot directly call another page - navigation is always done through an outisde page that "nests" inside pages. There are two components to nest pages: ROWINCLUDE and ROWPAGEBEANINCLUDE. In general we recommend ROWPAGEBEANINCLUDE because it is much smarter when it comes to build page modules that are generically usable.
Please check the documentation and there are also examples in the demo workplace (section: "General - Arranging Pages - Includes + General - Page Bean Binding").
...we now added a chapter in the documentation, explicitly demonstrating page navigation with page beans. Please check the newest version of the Developers' Guide (chapter: Page Bean Modularization).
There is (and already has been) also a chapter about "normal" navigation, which is based on pages (not on page beans).