ADE Help

First - I'm not a computer genius so please be gentle in your replies (I googled most of the wordings and solutions I'm tried).

I downloaded a library book onto my laptop - Windows 10.  The file folder I saved it in is My Digital Editions which is somehow connected to Acrobat Reader.  Reader will no longer open .ascm files so I downloaded Adobe Digital Editions.  I tried to change the default settings for .ascm files to ADE but it isn't listed as an option in the drop-down menu even though I have it installed. 

Now, instead of clicking on the download to open the book, I have to move the download into ADE to open it.  Yes only one extra step but there should be a way to fix this. Correct?

I would appreciate any insights anyone might provide.

Thanks.