[rcaban]

Originally Posted by underscore

do a long press on whatever file icon.
A context menu will appear and the "open with" will list every installed app able to cope with that file.

Thanks for the great advice but when I am in the Drpbox app on the Boox NP and long press that I, I don't see an OPEN WITH list. I tried to export the file in Dropbox and all looks fine until I select the folder on the NP but the file never downloads. It's almost like there should be a download button to end the task and I just don't see it.

Let's define folder.
From Library you can create "virtual shelves" with the icon close to the search one.
Long press --> move will move a book from the main library to the virtual shelf.
This is not like a real folder, if you browse the device from a computer, files are not changing position.
You can create real folders using the same icon from Storage.
The device will scan all the file system and present you everything aggregated together in Library.
If you want to distinguish comics, or work, or some series, virtual shelves in library is the way to go.

I managed to create the virtual library folder you suggested however I don't see any way to add files to it.

i don't like kindle app on nova either.
I de-drmed the 4 or 5 kindle books i own with calibre and i use neoreader as default reading app for mobi as well.

Great advice I will try this.