Okay kiddo, have you ever played hide and seek? Well, sometimes when we play, we have to point to the place where a friend is hiding to let someone else know where they are. We use our fingers to do this, right? Now imagine you were speaking a different language and you wanted to tell someone where your friend is hiding. You might use a special word at the end of the sentence to show that you're pointing to the place where your friend is hiding. This special word is called a case, and the delative case is one of those special words! It shows that you're talking about movement away from something or someone. It's like saying "from" or "out of" in English.
So let's say you're looking for your friend who is hiding in a tree. When you find them, you might say "I found him!" But if you wanted to use the delative case, you might say "I found him out of the tree." This shows that he was in the tree and then moved out of it.
In some languages, like Finnish and Hungarian, they use the delative case a lot when talking about movement or direction. And even when they're not talking about movement specifically, they might still use the delative case to show that something is moving away from something else. It's just like using our fingers when we play hide and seek - it helps us show where things are and where they're going!