A layout page is a document page on which you generally lay out all of the document elements. There you create text, place images and graphics, design all elements to your needs, and decide which objects shall overlap or cover others, or wrap around them.
Each document page has a layout page. If necessary (e.g. for
creative or management reasons), you can even use different layers on
each layout page. Use the Layer inspector
to manage multiple
layers. If you don't want to use layers, each layout page has one
layer nevertheless.
Think of a layer model, as far as document structure is concerned. At the very bottom you find the master page (which also has at least one layer). The layout page is placed over the master page (with at least one layer, too).
