You do it with Acrobat, not with Distiller.
In Acrobat look under Tools - Pages - Bates Numbering.
I realized after I wrote the question that it would be Adobe Acrobat Pro XI. I do not have the Tools option in my version, I have Common tools and it does not give me the same options…
Above Common Tools click on Customize and then on Default Tools and you'll see it.
Thank you so much!