Most good stories start with a fundamental list of ingredients: the initial situation, conflict, complication, climax, suspense, denouement, and conclusion. Great writers sometimes shake up the recipe and add some spice.
Initial Situation
From the beginning until the end of Book 1.
The end of Book 1, of course, when Eustacia learns that Clym is coming home from Paris, which basically sets everything else into motion.
Conflict
Book 2 – Eustacia and Clym meet and get married.
In the midst of falling in love, these two crazy kids manage to seriously anger Mrs. Yeobright (hence the conflict). This love affair is far from calm, and we have the ongoing conflict with Damon as well.
Complication
From Eustacia and Clym's marriage until Mrs. Yeobright decides to pay a visit.
Eustacia and Clym's marriage gets hurt by one problem after another, so the two grow distant. Damon and Thomasin aren't having a great time either. Mrs. Yeobright tries to give her relatives their inheritance, which of course goes badly.
Climax
Mrs. Yeobright tries to visit her son and ends up dying that night without ever reconciling with him.
Oh, the drama. This is the major turning point of the novel and Mrs. Yeobright's death sets the stage for all that follows.
Suspense
Immediately following Mrs. Yeobright's death until Eustacia leaves Clym's house after their fight.
The suspense is out of control here, given Eustacia's crushing guilty secret and Clym's obsessive need to find out about his mother's death.
Denouement
From Eustacia's return to her grandfather's house until her and Damon's deaths.
It's all downhill in this section, though not in terms of action – everyone is pretty much just doomed. The requisite tragic deaths occur here.
Conclusion
Book 6.
Everything wraps up here and the (surviving) characters get their endings, though not all are particularly happy.