You have created a report and are in the report view.
Go to the toolbar and select the "leaf and paper" modify icon.
Select the "Breaks" tab.
This area allows you to select any variable on your report. Select a variable and then select the "Start new page" checkbox.
NOTE: By default, this will create a new page for each new value of the variable. More advanced Conditions can be set in the "Condition:" dropdown and "Expression" area.
Related Documents: More information can be found on creating breaks in the Forest & Trees help under "Reports\Modifying Report Basics\Modify Report: Breaks" under the Contents tab.