Drawing Structure in CorelDRAW

Pages

When you open a new drawing with a blank page in CorelDRAW, you are like putting a blank sheet of paper (canvas) on your real-world desktop.

Objects

When you start to add objects to the page inside CorelDRAW, you are like gluing collage pieces (like the pink Polygon shape and text in the illustration) on that blank paper (canvas).
Object is a generic term for any item you create or place in a drawing. Objects include lines, shapes, graphics, text and groups of objects – child objects.

Layers

In CorelDRAW, organizing objects on layers is like gluing each group of related collage pieces to one transparent sheet (Instead of gluing pieces directly to the paper sheet), and stacking all the transparent sheets over each other. The stacking order of these transparent sheets and the stacking order of the objects on each sheet contribute the appearance of the paper they reside on.
In CorelDRAW, pages contain Layer/s and Layers contain object/s.

Master Layers

Desktop
In real-world, you can put more than one sheet on your desktop. On whatever sheet you are currently gluing (drawing, painting), you can see and reach the desktop. And you can move any piece of the collage outside the sheet, placing it on the desktop (the green "Text 1" in the illustration).
That's what happens inside CorelDRAW. When you put an object outside the page borders, you are moving it onto the Desktop layer. The Desktop layer lets you store objects that you may want to include in any page at a later time.
Note
To prevent CorelDRAW from sending objects you put outside the page border onto the Desktop, lock the Desktop by clicking the pencil icon beside the layer in the Object Manager (Tools > Object Manager).

Grid
The Grid layer contains the grid that is used for all pages of the document.
Guides
The Guides layer contains the guidelines that are used for all pages of the document.
Objects placed on any of the three master layers – Desktop, Grids and Guides – apply to all pages, while objects on Normal (Local) layers apply to their page only.
These three layers are the default master layers for new documents, you can add one or more master layers to hold content such as headers, footers and backgrounds.

The Master Page

To preserve the "Document > Page > Layer > Object" hierarchy, all master layers are grouped together in a virtual page; the Master Page.

CorelDRAW X4

Prior to X4, if Page 1 contains Layer 1 and Layer 2 for example, Page 2 will also contain two layers with the same names: Layer 1 and Layer 2. Same layer structure across the document.
In X4, you can control and edit layers independently for each page of your document. You can add guidelines to local and independent Guides layers for individual pages.