What you will do in order to track clicks is add the ;click= and <%%REDIR%%> into the redirect string as below.

<script language="javascript" src="http://track.adform.net/adfscript/?bn=43547;click=<%%REDIR%%>"></script>
<noscript>
<a href="<%%REDIR%%>http://track.adform.net/c/?bn=43547;c=0" target="_blank">
<img src="http://track.adform.net/adfserve/?bn=43547;srctype=4;ord=<%%unique%%>" border="0" width="468" height="60" alt="">
</a>
</noscript>

Note: this describes the usage of external non Adform related systems and please check respective documentation for most up to date information.