To add a new page create a work item on the parent page and from the dropdown select "workpaper". Add a title for the workpaper, decide what section it will appear in, and add a default conclusion. You may also specify whether you wish the page to be a "respawner" (able to create more than one version of the page say for multiple departments) and whether you wish the page to be created automatically whenever a job of this type is used. 
Clicking "save" will create the page as a work-item. You may then drag that item to wherever you wish on the parent page.
Click on the link to open the page, then you may add headings and work-items to that sub-page. 
Once the page is complete click "publish changes" and it will be ready to use.