This is a brief idea of managing advertisement banners and clients in Joomla CMS. Joomla provides us the facility to display advertisement banners via the core module banners.
   The default banner size is 468 pixels in width and 60 pixels in height. The banner can be placed anywhere in the web page as desired by you. The placement being decided by the template and more precisely by the position "banner" in the template. You can also choose which pages you want to display the banner by changing the settings in the module manager.