Just a short tip: If you want to create a link in a plug-in to a location within the (same) plug-in you have to do it in the following way:
$html->link('link', $this->controller->base.'/mycontroller/myaction');
That will create this html snippet:
<a href="/myplugin/mycontroller/myaction">link</a>

Don’t work if your app isn’t in the root.
Use this instead :
$html->link(‘link’, ‘/’.$this->controller->plugin.’/mycontroller/myaction’);
@Naonak: Thanks for the completion!