The Audit Trail subtab is exactly what it sounds like, an audit trail for every edit to an employee.  When you enter an employee's record and click on the Audit Trail subtab, you will see something like this:

You can minimize the sections if need be, as indicated by the yellow highlights.  You can also either click the Show All button or the refresh button (both are highlighted in blue).  The Show All button will open a new window with all of the audit trail information for the employee.  From there, you can print the full report if desired.

The button towards the upper right-hand corner that is highlighted in yellow will allow you to print.  The button to the right will close the window.