This could be a simple example.
[Employee.Employee_Account='[%CurrentUser%]']
Assume if Employee is linked with Account (a specialized entity of System.User). If you want to show only the employee details of the currently logged in user, the above XPATH is what is needed.
The below XPATH does not work. As you are already in the account entity.
[Employee.Employee_Account/Administration.Account='[%CurrentUser%]']
Hope this helps.