To get the audit report on an entry, your server must be licensed for audit and you must have the Retrieve Audit Data privilege granted from the administration console for your user. On the administrative side, the Web Access configuration page must have Audit turned on in the services tab and it must point to the server where Audit Trail is installed.  

If the above is true, your user will be able to see the Audit Trail link in the context menu for each entry, in the toolbar drop down for selected entries, and in the document viewer entry name drop down.