How to useState in React?

hey!

As a newbie, when I started react JS, I don't know where to start today I'm learning how use useState hook in react.

newbie code.

import React, { useState } from "react";
import "./App.css";

function App() {

  const [activated, setActivated] = useState(false);
  return (

    <div className="App">
      <h2>React useState Hook</h2>
      <p>I am {activated ? "on" : "off"}.</p>
      <button type="button"
        className="main-button"
        onClick={() => setActivated(activated ? false : true)}> 
       {activated ? "Deactivate Me !" : "Activate Me !"}!</button>
    </div>

  );

}

export default App;