^^^+1 if you want to learn what Jutoh is doing.
I also HIGHLY recommend taking an hour or two to learn the basics of html and CSS. There is a good tutorial at
W3Schools, and there are a few guides on
MR's Wiki.
It is really not that complicated and what you need for making a basic ebook is pretty...well...basic. I also recommend using an ebook editor that allows you to see the html code as well as what the result looks like side-by-side. I like Sigil, and Calibre Editor is good too. Good news is they are free! Those automated sites/programs can only do so much...and honestly, it makes me cringe when I see the junk they usually put out!
If you decide that your book is "not basic" then you should get a professional ebook maker. They will save you no end of hassles trying to get your book just right for all the different types of platforms out there.
Cheers!