For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
So in a three act plot structure, the first act is pretty much equivalent to the exposition. In Parable of the Sower, that's Lauren growing up in Robledo, scribbling out her religious verses without even having a name for her God-is-Change religion. She knows the security situation of her hometown is going downhill, but she hasn't decided to leave home yet, and she's still kind of feeling things out. Better get a move on, Lauren.
Act II
Act II is when the protagonist is struggling to achieve his or her goals. In this case, Lauren is migrating north trying to recruit followers to her religion. She kind of gets an easy start with Zahra, but after that, Lauren has to show kindness to strangers to win over some new faithful. She helps Travis and Natividad at the water station and wins their loyalty; Travis is her first big convert. Then Lauren's group wins over (to varying extents) more followers, including Allie and Jill Gilchrist, Emery and Tori Solis, and Grayson and Doe Mora. But will they stick around to build on Bankole's land? That brings us to Act III…
Act III
Here's the climax, what we've all been waiting for. In our Shmoopy opinion, the big moment in Act III is when Lauren asks everyone to say whether they'll stay on Bankole's land and build Earthseed with her—or move on. Everyone stays. And then things wind down, with the funeral service for their lost love ones, the naming of the place (Acorn), and so on. And if you really want more, be sure to check out the novel's sequel, Parable of the Talents.