Fear not I, a still rather confused individual, but with slightly more knowledge on the topic shall answer thy call (I seem to suffer from the curse referred to as "being genderfluid" by the scholars of that gender stuff)!

Somebody who is non-binary is just someone who does not feel like they are entirely male or female. This can mean that they are both, neither or a different gender not connected to either but also not entirely absent or of course any combination of the previous examples.

In my case (genderfluid) I just flop around on the gender spectrum, mostly not having a gender or feeling a bit feminine but sometimes I do feel male or like some other gender. Though genderfluid just means that the persons gender changes over time, it doesn't have to be the same genders that I experience.

Hope this helps :)