Can't see iPad in Digital Editions in left panel; Can't copy document to it

I am trying to move a Digital Editions document from my Mac to my iPad.

According to the online instructions, I am supposed to connect my iPad to my iMac via a USB cable and then load Digital Editions, at which point I am supposed to see a Devices section on the left panel of Digital Editions. 

• I am able to read the document on my iMac.
• I have closed out Digital Editions and connected my iPad to the iMac with a USB cable.
• iTunes on the Mac recognizes the iPad (IOS 9.3.5) and syncs with it.
• However when I launch ADE, I do not see "Devlces" in the panel on the left.
• So there is no way I can drag my ADE document to my iPad.

How can I solve this problem?