So once you have clicked on the Links and Tracking Icon, show on the previous page, you will then be presented with a new page, shown below

From that page, you then choose the banner icon at the end.

That will show you all the banners available to you to choose, together with the code you need .

Now as mentioned before, because this banner is going to go on the top of your right hand side bar, then the banner size should be no more than 350 Pixels, otherwise, when its added to your blog, it will look wrong.

So, click the banner icon you see below