please help? i dont know how to care for newborn hermit crabs!

They almost never breed in captivity unless you provide very specific conditions. You don't need to worry about it. They don't even bother separating the sexes in the store.

Unless provided specific conditions, hermit crabs will not mate in captivity. Mating hermit crabs in an estuary is a very costly and pain-staking procedure. So, no need to worry about your pet hermit crabs mating - most times, when buying crabs at a pet store, not only are the males not separated from the females, but the majority of pet stores do not have them identified as either or.