Imagine you have a box of toys. All the toys inside are different, but they are also alike in some ways. For example, some toys are big, some are small, some are red, some are blue, some are soft, some are hard.
Now imagine a family where there are a mom, a dad, and two children. Everyone in the family looks different - the mom has brown eyes, the dad has green eyes, the sister has blonde hair, and the brother has brown hair. But they also share some similarities. For example, they might all have the same nose shape, or they all have a similar laugh.
That's what family resemblance means - even though each family member is unique, they also share some traits that make them part of the same family. It's like how all the toys in the box are different, but they also have some things in common.