Imagine standing in line at a coffee shop, the place is brimming with people all shouting their order at the one overwhelmed barista. You place your order but he can’t hear you. You shout it, you scream it over the din of the thousands of people also ordering their coffee, but the barista just shrugs because he can’t get your order much less process it. No coffee for you. As you leave you realize those thousands of other customers aren’t even customers, they were just noise generated to keep you from getting your coffee.
Welcome to DDoS.