The order in which the normal pages appear in the Structure area determines the order in which the document executes them. Normal pages are always executed from top to bottom, once per datapage, unless this order has been modified by the use of a RunPage (see Creating and using Runpages), or a Repeat object (See Line Repeat and Data Overflow).
You can change the execution order of the pages by changing the order in which they appear in the Structure area.