I came from vBulletin. There we have conditional code in the templates like this, which I use to display advertisments (to not logged in users) oder not (to logged in users) ==>
<if condition="!in_array(THIS_SCRIPT, array('register','login'))"> <if condition="$vbulletin->userinfo['userid']">
<if condition="in_array($post['postcount'], array(3))">
Any tips are welcome, thank you very much.