Perfect

But now i am a bit confused !
What is the best for me : store books in EPUB format, and only convert them to AZW3 when i upload them to my Kindle, or store them already in AZW3 in calibre file structure ?
If your advice is to store them in Calibre in AZW3, how do i convert them when i import a book into Calibre, from an epub file ?
Thank you very much again theducks !