Can you clarify the composer autoload issue?

Question

PHP

I downloaded the library https://packagist.org/packages/dakota/pchart to my project using composer .
When I try to call the class, it gives the error "Class not found". How do I load this class, shouldn't Composer do it automatically? Plus, in my project I use namespaces. And in this library they don’t exist at all, what to do in such a situation? Explain, please, since I use composer only for the second day.

Answer 1

1. Have you included vendor/autoload.php?
2. If you are talking about this library, then autoload is not configured at all in composer.json.

Answer 2

composer dump-autoload -o