phpAdsNew is really complicated but at the same time very very powerful!
We are using the same to rotate the ads on our site. :-)
Now, you in the advertisers page, you make a campaign and put up the banners or any banner code from a third party company.
Then you go to the publishers page, and create a publisher, link the banners that you want for that publisher and then generate the code. Well, If you browse through the interface for some time and try some experements, you will learn it on your own ( the way I did ). Else, go to their official site and download the PDF manual.