My pdf.acsm is not shown upon Digital Editions.

I use Galaxy Tablet, SM-P585, also known as TAB A6 with S-pen.

I've installed Digital Editions App from GooglePlay.

I downloaded my E-book from GoogleBooks into Booktitle-PDF.acsm

I doubleclicked the file, then Digital Editions occured, but there's nothing.

I tried to open it from the start of Digital Editions, but failed; I activated the App alone, and tried to find a menu of "Add new file", but none, just these 4 menues there.

-Library

-Favorites

-Recently Added

-Settings

How can I activate my Ebook-pdf.acsm downloaded from Googlebooks?

I'm so eager to read and write on the PDF.

I'll appreciate for your all effort, in advance.

Kind regards.