Hello 
1. Download the Plogger last version... and,
2. Is very simple, create a new page whit this code:
<?php
define('PUN_ROOT', './');
define('PUN_QUIET_VISIT', 1);
require PUN_ROOT.'include/common.php';
//Set the page title here
$page_title = pun_htmlspecialchars($pun_config['o_board_title']) . ' / New page 1';
define('PUN_ALLOW_INDEX', 1);
require PUN_ROOT.'header.php';
require PUN_ROOT.'include/parser.php';
?>
<div class="block">
<h2><span>Gallery</span></h2>
<div class="box">
<div class="inbox">
<?php require("../path_to_plogger_folder/gallery.php"); ?>
<?php the_gallery_head(); ?>
<?php the_gallery(); ?>
<p>
All Photos are copyright... Bla bla bla...
</p>
</div>
</div>
</div>
<?php
require PUN_ROOT.'footer.php';3. Save as gallery.php and put in PunBB folder
4. Create the page in forum options: X = <a href="gallery.php">Gallery</a>
PS: in path_to_plogger_folder, I presume that PunBB is in /punbb/ folder and Plogger is in /plogger/ folder.
PS2: I went to punwiki in mini portal tutorial and there was a tutorial how to create a custon page