Questions about xefx from a noob

Hey, I am trying to learn how to use this. However, I don't know any JASS past the beginner tutorials and blade's tutorial. Could you explain to me what a struct, a method, and a library is?

Methods, structs, and libraries are all 'new' additions to the JASS language made possible by Vexorian's JASSHelper precompiler. The new incarnation of JASS (called vJASS) is much more object-oriented and includes bunch of stuff to make coding, well, easier.

It's a bit out of date, but you should start here for a good tutorial. As for a more in-depth analysis of vJASS itself, I would look at the JASSHelper manual, which is included in the JassNewGen Pack (the online manual is a bit out-of-date).

Here is the online version of the JassHelper documentation, even if it's not the latest version it should be good enough for getting a basic feel for vJass.