I suggest maybe you can get minecraftbooks for kids, I usually go yo library for that but those books are usually very new and too popular to be available. And I don't want to wait so purchased a lot from anazon. By last month, I guess I already purchased almost all helpful instructive books for minecraftbooks from amazon.it keeps coming out new books, it's just TOO popular.:)

And if your kids love searching internet I think minecraft official website forum is the best one to get a lot of tips.