If this has been asked a million times already, my apologies. I am not a patient person, and I do realize that not everyone will use the same terminology when starting out with a new program.
I've been using Calibre for a couple of weeks, and I find that it is really doing a good job on what I'm guessing is the simple stuff.
I have a Kindle (and Kindle apps on my iPad and iPhone). I haven't gotten brave enough to try any plugins, but I have been converting lots of epubs to mobi, and some pdf to mobi with great success. (I only read on my phone when I'm stuck somewhere and forgot my Kindle, and I rarely read on my iPad because it is just too heavy.)
So you can see, mobi is my conversion of file type of choice. I have looked in preferences and there doesn't seem to be a way to do this. It is frustrating because I don't always remember (yet) to check the dropdown in the upper right of the conversion window.
I ask your patience with a newbie who is not unfamiliar with computers and programming (I am already delving into using regular expressions in the search and replace page of conversion), and who just loves to read. I used to have more than five thousand paper books, now I'm working on going all digital.
Thanks for your patience
Mad