This novel doesn't have a particularly complex plot structure. It is autobiographical in the sense that it is told in first person and follows Jane's life from her youth to her happy marriage and life with Mr. Rochester. The structure is simple--it follows the stages of Jane's life from age 10 to her contented adult life.
The story begins when Jane is young and orphaned and living with some distateful relatives; she spends little time there, then she is transferred to an orphanage. We see her early days there, then she leaves to make her own way as a governess. We see her as a governess for a short time (although a lot happens in that short time, including a dramatic scene at the altar), then she leaves to do something, somewhere. We see her as a lost soul taken in by apparent strangers (and nearly trapped in a loveless marriage of convenience), then she follows her instinct and heads toward Rochester. She discovers him (in a pitiful state, of course), and she commits herself to him for the rest of their lives.
There are no flashbacks, no changes in setting other than those few spots (not much, considering it's a long novel), and no dramatic plot twists other than one--the fact that Rochester is already maried to an obviously mentally impaired woman. That one twist, however, sets Jane's course for the rest of her life. It is the center of the only mysterious things in the novel (though many of the places are rather eerie and foreboding, since it's a gothic novel), and it is the crucible by which Jane's moral resolve is tested.
In short, it is a coming-of-age novel, told in first person, following the life of a poor, orphaned girl.