Hello
This component is mostly used to allow users to submit baners and bid for spaces from the front end.
As describred in the documentation:
Prepare your site
Visit your site and define the spaces you want to offer as Banner Auctions.
Define the corresponding allowed Banner image/swf sizes. For your information most usual banner sizes are listed here:
designerstoolbox.com/designresources/banners/
In core Joomla Banners component , define a (new) category as 'Advertisers (only) category' for Auctions.
For each of the banner sizes you selected, you must create a banner category within the Adverisers category (as children categories). Auctions are set wirthin each banner category (inside the main advertisers category). In the category name you set, it is a requirement that you also set the category banner size tag. Just like [250x250] where 1st 250 is the width in pixels and the 2nd 250 is the height in pixels. For example a category name could be: Square Banners [300x300]
Set new banner modules for each banner subcategories you created.
Let me know what's not clear.