set the "document root" to the public folder inside your project

HI, first sorry my english, it's not the best. I am new in CI 4, although I have experience en CI 3. MY problem is quite comented in other post.
I copied the CI 4 code in my web server , the same directory when I have a project with CI 3. The name of the folder that contains the CI 4 code es CI4, so http://localhost/CI4 should be the way to access to the welcome message. But the CI return
"If you see this message, you have not configured your web server properly.
You need to set your "document root" to the code public folder inside your project. This could be your default setting, or that of a virtual host, depending on how you set up your local development environment.".
I set

Code:

public $baseURL = 'http://localhost/CI4/public';

in application/config/app.php.
In other post I read set it to

Code:

'http://localhost/CI4

only but the problems persits in both case.
What the problem? What can I do?
Thanks