Composer create local package

In my project inside the vendor directory I created a new directory named Hello and created a new class HelloWorld.php with the namespace Hello\Test. Then in the root of Hello I created a composer.json with default meta data (author, license, desc, required), and added autoload PSR-4 Hello\\Test\\.

So what do I need to do next to autoload my package. I looked at some Symfony components and their composer.json package and configuration is the same.

Is it possible to autoload my local package from vendor like this?

Dir structure:

|-my_project
|-composer.json
|---vendor
|-------composer
|-------autoload.php
|-------Hello
|-----------composer.json
|-----------HelloWorld.php

./vendor/Hello/composer.json

{
  "name": "Zend/Hello",
  "description": "My test package",
  "license": "MIT",
  "authors": [
    {
      "name": "Zend Zend",
      "email": "test@example.com"
    }
  ],
  "autoload": {
    "psr-4": {
      "Hello\\Test\\": ""
    }
  }
}

My HelloWorld.php class has namespace Hello\Test; Inside index.php i do include 'vendor/autoload.php And root composer.json

{
  "autoload": {
    "psr-4": {
      "": "src/",
      "Hello\\Test\\": "./vendor/Hello"
    }
  },
  "require": {
    "Hello/Test": "*"
  }

}

composer update