ClickBook comes with sample documents for most layouts. Most of the documents are Microsoft Word documents that can be used as a starting point when creating booklets, tri-folds, french folds, labels, etc.
The reason for including sample documents is that some of the layouts require specific margins, or number of pages to work properly with the layout. The sample documents will be pre-set with those pages, margins and other page settings.
To use a sample document, simply choose the layout you wish to use, then hit the Samples button on the toolbar, or choose Help->"Sample Documents..." and then hit "Use this layout with its sample document"
The sample document will be loaded up in Word or other word processor and you can modify the contents to meet your needs.