Have you read through the wiki? It explains all you need to get started
http://www.zen-cart.com/wiki/index.php/Main_Page
to answer your question though look in your admin/tools/banner manager, click the green dots to make them red then refresh the page of your shop front, you will see the banner has gone. You can of course create your own banners to use as you wish, the ones you currently have are all just samples.
Posted via Mobile Device