Originally Posted by Cdesja5
You can add them to Aldiko using the "file" icon in the Aldiko main menu. I don't have my tablet with me but I believe you will find the books in the "ebook" folder.
And, for the epubs (assuming DRM-free), you can place 'em on the Arc (pretty much anywhere - I, as usual, prefer to dump stuff into "Download") and use the Import Content option in the Kobo app to add them to your Kobo library, if you want to use their app. [just tested and it had no problems finding the book I placed in the Download directory]