Okay kiddo, a board support package is like a special set of instructions and tools that help grown-ups make electronic devices work.
Imagine you have a toy car and you want to control it with a remote. But the remote doesn't know how your toy car works, so it can't control it. A board support package is like a bunch of instructions you give to the remote, telling it exactly how to control your toy car.
Now, instead of a toy car, think of a more complicated device, like a computer or a phone. There are many different parts inside that talk to each other to make it work. But all those parts need to work together in a specific way. That's where a board support package comes in.
It tells the different parts how to talk to each other, how to share information and how to get things done in the right order. Basically, it helps everything work together as a team.
So, it's like a bunch of recipes that explain how to cook an amazing meal. Except, instead of food, it's instructions that tell your device how to work properly. Cool, huh?