first, on the login page, you need to edit the code to store the user name in a session.
find the following code:
"sessionColumns" => explode($WA_Auth_Separator,"UserID".$WA_Auth_Separator."UserEmailVerified".$WA_Auth_Separator."UserEmail"),
"sessionNames" => explode($WA_Auth_Separator,"UserID".$WA_Auth_Separator."UserEmailVerified".$WA_Auth_Separator."UserEmail"),
and change it to:
"sessionColumns" => explode($WA_Auth_Separator,"UserID".$WA_Auth_Separator."UserEmailVerified".$WA_Auth_Separator."UserEmail".$WA_Auth_Separator."UserFirstName"),
"sessionNames" => explode($WA_Auth_Separator,"UserID".$WA_Auth_Separator."UserEmailVerified".$WA_Auth_Separator."UserEmail".$WA_Auth_Separator."UserFirstName"),
then you can use this code to show the user session:
<?php
@session_start();
echo(isset($_SESSION['UserFirstName'])?$_SESSION['UserFirstName']:"");
?>