Tutorial markdown changes for React18 (#4630)

* Changing the markdown - Initial commit

* Adding the missing instruction to copy the JS and CSS from starter code

* reverting the extra text added

content/tutorial/tutorial.md

@@ -106,7 +106,7 @@ cd ..
 
 ```js
 import React from 'react';
-import ReactDOM from 'react-dom';
+import ReactDOM from 'react-dom/client';
 import './index.css';
 ```