The language of Slaughterhouse-Five is straightforward, so it's easy to understand what's happening in each of the sections. But with all the time jumping, alien abduction, and heavy-duty philosophy, it can be tough to work out how the sections go together.
This is definitely a book where you can lose track of what's happening where and when. Luckily, as the book points out, "when" is totally subjective. You can totally let yourself get lost—Vonnegut will find you again.