Do you know how to hit a dragon with an ax? Do you know how to cast fireball? Roleplaying isn't about being precise or effectively knowledgeable in the unknowable, it's a game of pretend and what you make of it. The rules are a guide for outcomes not hard lessons in acting and research. My suggestion, listen to some Slayer, watch Until the Light Takes Us, light some ceremonial candles and pretend you are a demon who can play guitar.