Below is the html & css code to change the Categories.
HTML Elements - File located at - index.php
---------

$category = amCategory::getById(39);
$file_row = array(
                'files' => amFile::search(array('order' => FILES_ORDER_VIEWS, 'limit' => 5,
                                     'types' => array($type), 'category' => $category)),
                'title' => 'Top 5 Sport'
             );
array_push($files, $file_row);

Theres two main parts you need to change that will influence what kind of information the categories will display.
Where you have FILES_ORDER_LAST_VIEW_TIME,

Can be substituted with either:
FILES_ORDER_LAST_VIEW_TIME, - To Order via last view time
FILES_ORDER_UPLOAD_TIME, - To order via last Uploaded time
FILES_ORDER_VIEWS, - To order via Most Viewed

Where you have amCategory::getById(39);
This line points to the category id, which can be viewed from either 3 locations.
1) Hovering over homepage Categories with mouse
2)Inside admin Category section
3)Viewing the id directly from the database
So in our case 39 is the Sport category and will show all Sport Videos.

Another part that you can modify is the title
Where you have - 'title' => 'Top 5 Sport'
You can adjust the text to display the text any way you wish.

Another part that can be adjusted is:
'limit' => 5,
This tells the script how many videos to show, if you're handy with coding, you may display the Video thumbnails in vertical format and increase this limit to something like 10.

HTML Design elements that control the categories - templates/frontend/home/index.tpl

<div class="content">
				 <?php foreach ($file_row['files'] as $file): ?>
				     <?php echo $file->getShortPreviewHtml() ?>
				 <?php endforeach; ?>
</div>

CSS Elements - css/style.css - line 111
============

#videos #top .content, #files #top .content, #images #top .content {style.css (line 111)
background-color:white;
float:left;
padding-bottom:5px;
width:750px;
}