Honestly I am not the best to explain it because of its sheer complexities. Quantum mechanics "broke" our classical way of understanding physics and this is super high-level physics. I take the simple approach that isn't entirely correct but gives you the base idea that the idea of computers being only 1 and 0 is gone. For example, in one type it can be both 1 and 0 at the same time. Qudits for example encode more than just a 1 or a 0