#THIS IS THE PHP FILE
<?php

require_once("smarty.php");

echo 'this is my code';
$smarty->assign('test','123');
$smarty->display('index.tpl');

?>

$THIS IS index.tpl in folder TEMPLATES

<html>
<head>
<title>SMARTY TEMPLATE TEST</title>
</head>

<body>
It's as easy as {$test}.
</body>
</html>