Okay kiddo, so imagine you have a big box of toys that you want to play with. But you don't know which toy to pick first. So you decide to make a robot that can help you pick out toys to play with.
This robot is called a computer, and it has a special ability. It can remember things really well (kind of like how you remember all your friends' names!).
A computer with the ability to remember things is called a stored-program computer. It's like a toy box with a list of all the toys inside. The computer can read the list, or program, and use it to do things like play games, read books, or help with homework.
The program is stored in the computer's memory, which is like a very big brain that can hold lots of information. And just like you have to follow the rules when you play with your toys, the computer has to follow the rules in the program to do what it's supposed to do.
So that's what a stored-program computer is – a smart robot that can remember things and follow rules so it can do all sorts of neat things for you!