whats the plot sturcture?

Answer 1

The way in which the author plans (structures) a story:
http://en.wikipedia.org/wiki/Plot_(narrative)#Freytag_on_Plot
Read carefully.

Answer 2

There are a few different models. A common one is that there is an introduction or exposition, an event, rising action, a turning point, a climax, and a conclusion that resolves the problem.

A good description to help you out is here:

http://english.learnhub.com/lesson/4579-plot-structure