your query is correct already:
SELECT *
FROM PD_Courses
WHERE PD_Courses.CoursesID = <?php echo $eCart1->DisplayInfo("ID"); ?>
ORDER BY DisplayOrder ASC
you just need to place it in a cart loop along with the code to display it:
<?php while (!$eCart1->EOF()) { ?>
<recordset here>
<code to display record information here>
<?php
$eCart1->MoveNext();
}
$eCart1->MoveFirst();
?>