Kobo reader

Hello. I have a kobe clara ereader. I bought I new book last week and when I tried to find it I realized that I couldn't see it. Trying to find the book and following all the proposed steps I lost all the books. I even made factory reset. I didn't have any result. So I bought a new reader. I cannot transef any book. What do I do wrong? I bought again Kobo Clara, so I know the right procedure. Is it something wrong with ADE? Please help me (I don't get any messages. After transfering the book I open it and I see that it is still empty)