The sponsored by text is located in the Global Settings section of the vb.Sponsors Manager. See the first screenshot posted in the original post.
You add the sponsor's banner by going to the forum manager and editing the forum you want sponsored.
Also, be sure you check out the docs located at
http://www.digitaldeviation.com/docu...ion/vbsponsors. There's a user's guide and an installation guide that will walk you through everything.