Waow thanks

Indeed it seems a bit complicated, but I guess I'll handle it after a few reading ^^
btw I wonder, is Calibre the best tool to convert books? And, I wonder as well, it does not exist tools to edit mobi files, so I have to create an ePub file before, right?
Oh and if I follow your tutorial, I end up with chapters but then the chapters are displayed as html code :
<p class="calibre1">Jetsam</p>
This is not very good, I mean... I would like to have a given class for chapters so I can decide how I want them to be displayed. And if possible I would like to keep the <hr> so to have an horizontal line after the chapter name. I guess this is all about fine tuning the convert thing...