Whenever you open a new, blank document (from the File menu, click Open, or press CTRL+N), Microsoft Expression Design creates an artboard in the middle of a very large white area. The artboard, also named the document frame, represents the intended output area of your file. Also, live effects are visible only in the artboard area. You should usually match the frame size to your output size.
You have two ways to change the size and shape of your artboard:
Use Artboard Size to change only the size of the artboard without affecting the objects on your page.
Use Document Size to change the scale of all the objects on your page.
To change the size of the artboard without affecting the objects
On the File menu, click Artboard Size (or press CTRL+ALT+C).
In the Artboard Size dialog box, select the measurement units you want to use. (If you select Pixels, the artboard size will be based on your current document resolution.)
Adjust the Width and Height fields. If you want to adjust the frame size by a relative amount instead of a specific page size, enable the Relative check box. For example, when the Relative check box is disabled, typing 150 px into the Width field changes the width to 150 pixels. When it is enabled, this adds 150 pixels to the current page width.
Specify where you want to position the page objects relative to the new document size. You can do this by clicking one of the nine Anchor buttons. For example, if you click the upper-left Anchor button, the artboard will extend or contract based on the upper-left corner of your current frame size, and all objects will be pinned to that upper-left corner point.
To change the scale of all the objects on your page
On the File menu, click Document Size (or press CTRL+ALT+P).
In the Document Size dialog box, adjust the Width and Height fields. To make sure that your document will scale proportionally, select the Constrainproportions check box.
The value that you specify in the Resolution field determines the native resolution of your document, and the resolution at which live effects will be rasterized. Note that some live effects, primarily the artistic effects, are resolution-dependent, and if you change your document resolution, the effect might appear different.