It's really quite simple:
1. MySQL database connection
$db = mysql_connect("hostname", "user", "password"

; //(substitute with your database hostname, username, and password, keeping quotes)
$query = "SELECT * FROM benefits WHERE employee_id=$employee_id";
$result = mysql_db_query("databasename", $query) OR die(mysql_error());
2. Since you are only calling one record, there is no need to loop the rowsource array
$r = mysql_fetch_array($result)
$field1 = ($r["field1"]);
$field2 = ($r["field2"]);
$field3 = ($r["field3"]);
3. 'Sprinkle' the PHP values inside the XML tags
<field1><? echo $field1 ?></field1>
<field2><? echo $field2 ?></field2>
<field3><? echo $field3 ?></field3>
(You get the idea. If you are displaying more than one record, you enclose Part2 and Part3 inside a while loop for the rowsource array $r)