"I will break it down like this." To "break it down" means you're going to say what it in smaller parts instead of all together, usually to make it easier to understand. Saying "like this" indicates that you are about to explain how you're going to break it down. An example would be: "I'm going to explain to them how to make a cake, I'll break down like this: first I'll tell them what ingredients they'll need, then I'll explain how to mix them together, and finally I'll explain how to cook it."