I tried to prepare my girls by reading them a few bits from 1001 Nights and watching Aladdin but they didn't really get it and were impressed more by the freedom to roam through the park than any story or even the sculptures. They totally and irreversibly fell in love with the light trees and now I have to figure out a way to replicate them for their birthday parties!
It really is a must-see for the whole family. If you go, be aware that entrance is KD 3, except for children under 3 which are free. The P2BK exhibit is free (its right next to the sand park). Also there are amazing light shows and events in the evenings and on weekends. Be prepared for crowds, parking far away and walking a lot. I would say that if you have younger kids, take a stroller and bottles of water. Map