1.) Go to your admin page and login. (
www.yoursite.com/admin.php)
2.) Select "Preferences" icon and scroll down to "Banner Options" and make sure it's "Active"
3.) Go back to the admin page.
4.) Click the "Banners" icon with the dollar sign.
5.) Fill out the information.
6.) Should be done and viewable on the top.
EDIT:
I noticed on your website you have the error messages all over the place. To remove that, open your mainfile.php and locate:
After that line, create a new line and place:
on the new line. Save and upload. Error messages should be gone. It worked for me, hope it works for you.