Click Portrait (tall) or Landscape (wide). These icons interact dynamically with the dimensions you enter in Page Size. When Height is the larger value, the portrait icon is selected. When Width is the larger value, the landscape icon is selected. Clicking the deselected icon switches the Height and Width values.
Tip: To specify the dimensions of the bleed and slug areas, click the Arrow button before the Bleed and Slug label in the New Document dialog box. To make the bleed or slug areas extend evenly on all sides, click the Make All Settings The Same icon .