Usually, “instructions” refers to something that provides information: the instructions for how to assemble a chair; “directions” is more likely to refer to something more like orders: she expected her directions to be followed.

The trouble is that in real life, it often works the other way around. We say that someone gives “directions” to someone’s house (not usually “instructions” on how to get there), and “instructions” in the context of education can mean laying down the rules.

So, your question is not at all stupid. This is one of those word pairs where the definitions don’t exactly help you much with how the words are actually used. You just have to develop an ear for where one makes more sense than the other.