Can someone please explain the takeaway from Kafka on the Shore?

I just finished reading the book and I loved the writing, the depth in character, the prose, the weird oddities but sometimes felt very confused [I don't know if it is meant to confuse us, but what was the whole Kafka/Ms Saeki/Sakura plot and the whole stone aspect? How did Hoshino close the stone by just lifting it?] Please just help me understand the symbolism and not the literal understanding of it. Thanks!