In Walk Two Moons, Sal uses her memories in order to hold onto her mother and to make sense of her place in the world. Her memories pop up like bubbles to the surface of a pool, and it is through these memories that we get a sense of the events that led her to the present moment. Of course these memories don't always arise chronologically, but the order in which she remembers them shows us how she is putting the pieces of her life together. Sal's memories are both painful and helpful, sad and happy, and everything in between.
Memories help Sal forgive her mother.
Once Sal is able to let go of the past, she is able to move on with her life.