Most documents use two-page spreads exclusively. When you add or remove pages before a spread, the pages shuffle by default. However, you may want to keep certain pages in a spread together. For example, you can create gatefold or accordion foldouts by creating a multiple-page spread (also called an island spread) and adding pages to it. By not allowing pages to shuffle, you can ensure that pages are kept in the same spread.
To keep a single spread together, select a spread in the Pages panel, and then deselect Allow Selected Spread To Shuffle in the Pages panel menu. You can identify an island spread in the Pages panel by the brackets around its page numbers.
To allow the creation of spreads of more than two pages in the entire document and to preserve those spreads when you add, remove, or arrange preceding pages, deselect Allow Document Pages To Shuffle on the Pages panel menu. InDesign will preserve spreads of more than two pages while letting two-page spreads repaginate normally.
You can redistribute a spread’s pages to match the Facing Pages setting in the File > Document Setup dialog box.
If an individual spread has been allowed to shuffle, select the spread, and choose Allow Selected Spread To Shuffle in the Pages panel menu to select it.
If document pages have been allowed to shuffle and you added pages to a spread, choose Allow Document Pages To Shuffle from the Pages panel menu to select it. Click No to redistribute pages. If you click Yes to maintain the multiple-page spreads, brackets surround the numbers on those spreads in the Pages panel, indicating that those spreads are not allowed to shuffle.