DVDA4
Is it possible to create a single-page menu that has scenes? In other words, the Parent menu should have buttons that go to scenes, with no need for a sub menu.
Yes. Add source to menu, add chapters to source, then copy initial button once for each added chapter. For each button then set Action to appropriate chapter. You'll probably also want to change the images and names to reflect the chapter content.
Another method is to start by creating a Single Movie project (File > New > Single Movie) and adding your chapters. Then, in the Project Overview window, right-click the movie and choose "Insert Scene Selection Menu." Last, select the Scene Selection Menu in the Project Overview window and hit the Set DVD Start button (the icon of a purple box with a star).