What is the easiest way to do this?

I don't use Newsstand, but I am pretty sure it's only for magazine/newspaper subscriptions. As in, you can't move PDFs to the Newsstand app.

Sorry, but Newsstand is designed to help major publishers sell subscriptions. So, iBooks reads PDFs, Newsstand doesn't.

Marilyn

That is correct. Only apps that are created for Newsstand will show up in Newsstand; apps, not book or magazine files, even though they display like a file in the stand.

You'll find the compatible apps under the Newsstand category in the App store. Quite a few magazines have not migrated to the Newsstand, so you'll still find many magazine apps under other categories, like News, LifeStyle, or Books.