Thanks for your pamphlet ›Quick and Dirty ePub Tutorial - v2.pdf‹
I just had a look at it and found a mistake: The little code starting with <h1>This is a level 1 title</h1> has to be applied in the source code of the html-file. Otherwise you just see what you have typed.
I have attached my file after having inserted the code in the source code. Above is what you suggested, below shows what I mean.
Best wishes Harry