Hi, Petr!
To see the syntax:
1) Create a bookmark (while playing a movie press Alt+I)
2) Edit the bookmark (while playing a movie press Ctrl+Alt+I)
3) In the Bookmarks Editor window click on the button Export as chapters
It will save a .chf file with you chapter at the same point of your bookmark.
Now all you have to do is edit your text file containing the chapters of the movie you want that for...
I hope this can come in help :!:
Cheers, Tizio