Don't know anything about the augen so I will be dealing with the issue from a very general level.
Most electronic readers are tied to a specific store and you will be forced to buy from that particular electronic store. The Kindle is tied to Amazon, the Nook and Noock Color are tied to Barns and Nobles and even my Libra Pro is tied to Kobo and Borders. Looks like to me that yours is tied to ebooksmedia.com.
Next, looks like you will need Adobe Digital Editions (its free) to acomplish the uplaoding of documents, www.adobe.com/products/digitaleditions
. My libra pro used digital editions and what I did was once I bought the book, go to my bookshelf and look for an icon that says download. That will transfer the book to digital editions and will bring it up in digital editions, hook up your augen to a usb port and digital editions will recongize it in the tree on the left. Next drag the book to the augen in the tree and digital editions will take care of te uploading.
This method is referred to as side loading and does not use the wifi, sorry don't know anything about the wifi.