The frontend layout is normally set to default. However, there are three other layouts available; if they are defined, you can use them. The marking as new is especially interesting for news pages, because you can display the latest news with a content element. You do not need to pay attention to the backend layout any further.
If you want to show the content of another page on the current page, you only have to select the relevant page here. For a news page, this option is located on the General tab. For reference and category pages, this option is not available.