So far, we’ve learned how computers use switches, wires, memory, and bits.

But who’s in charge of all of it?
Who says:

“Add these two numbers. Now show this word. Now open that game.”

That boss is the CPU or the Central Processing Unit — though we won’t call it that just yet.

Let’s call it:
👉 The Brain of the Computer

🧠 This Brain Doesn’t Think — It Follows

Unlike your brain, this one doesn’t make guesses.
It doesn’t feel or daydream.

It just:

1. Reads instructions

2. Does exactly what it’s told

3. Then moves to the next one

4. Again. And again. And again.

And it does this billions of times every second.

📜 What Are Instructions?

An instruction is just a tiny command:

• Add these two numbers

• Show this letter on the screen

• Save this file

• Move this image 1 step to the right

Each instruction is made of bits, just like everything else.

The Brain reads these bit-patterns and says,

“Ah, okay. Do this. Next!”

📦 It Needs a Recipe

The Brain needs steps — in the right order.

That’s what a program is.
Just a long list of instructions written in computer language.

Like:

• Step 1: Add

• Step 2: Store

• Step 3: Show

• Step 4: Repeat