thank yo all very much, in particular jswinden for his exhaustive answers
this is how i will proceed: taking notes with a kind of wordpad with just basic basic html, not to get distracted form studying
when i finished i will use dreamweaver (which is one of my fav editor) to set up all the layout, images and so on; import that in Sigil to create a ToC and to convert in an .epub and then convert it into a .mobi using kindlegen
But i don't really understand one passage: how do you "manually convert" the .epub in a .mobi? i don't get the part "When I compile the book I point Kindle Previewer to the toc.ncx file, not to the ePub file."
thx in advance