the links should contain a URL variable with the ID, for example:
?ID=1
looks like your link s in the header are missing the URL variable, for example:
<a href="gcs-news-details.php?ID=<?php echo $row_recordsetName['IDColumn']; ?>"><h2>This is the header</h2></a>
where recordsetName is the name of the recordset used to populate the news title and IDColumn is the name of the id column returned by the recordset.