How to move or copy books in a library?

My old computer died. I've installed ADE again, but the library is empty (apart from the welcome note) and does not contain any of my books.

I have a backup of the books I had in my library, but copying those does not result in them being added to the library. (The location where the books are kept has changed in the latest version of Windows 10. Instead of username\my documents\my digital editions, as it used to be, apparently it is now using username\onedrive\my documents\my digital editions).

And, yes, the books were bought with the same Adobe ID. I could copy them without a problem between my old PC and my laptop.

So, how can I copy the books I have back to ADE?

(Or how can I force ADE to use the local my documents instead of the onedrive my documents folder?)

Thanks in advance.

Manuel