Adobe provides two options when you begin a new document in InDesign. The default option is a two-page spread similar to a book layout. If you deselect "Facing Pages" in the new document dialogue box, you can view single pages. But what if your design calls for a three-page spread? For example, you may need to create an accordion-style document or perhaps you want to take advantage of the new multiple-page size tool on InDesign CS5 to add a flap to a book cover. InDesign does allow you to create three-page spreads.
Click on the "Window" menu and select "Pages" to open the pages panel.
Click on the pages panel flyout menu and select "New Master."
Type "3" in the "Number of Pages" box and press "OK." A three-page spread will appear in the Master Pages section.
Select all three of the new master page and drag them to the pages section of the panel. InDesign will add the new three-page spread to your document.
Select the pages where you want to create the three-page spread.
Click on the pages panel flyout menu and deselect "Allow selected pages to shuffle."
Drag a master page into the spread until the cursor changes to a hand with an arrow holding a page. Release the mouse and you will see three pages on one spread.