Magento – Magento 2 – sales-order-increment-prefix is not working

Change below code:

<admin>
        <routers>
            <adminhtml>
                <use>admin</use>
                <args>
                    <modules>
                        <orderstatus before="Mage_Adminhtml_Sales">Bromo_Orderstatus_Adminhtml</orderstatus>
                    </modules>
                </args>
            </adminhtml>
        </routers>
    </admin>

to:

<admin>
        <routers>
            <adminhtml>
                <use>admin</use>
                <args>
                    <modules>
                        <orderstatus before="Mage_Adminhtml">Bromo_Orderstatus_Adminhtml</orderstatus>
                    </modules>
                </args>
            </adminhtml>
        </routers>
    </admin>

Change controller code as below:

<?php
require_once 'Mage/Adminhtml/controllers/Sales/OrderController.php';

class Bromo_Orderstatus_Adminhtml_Sales_OrderController extends Mage_Adminhtml_Sales_OrderController {

    public function afhalenmailAction() {

         echo 'Test action';

    }

}

You have to create database 1st from command line or PHPMyAdmin. After creating database, run below command to install using command line.

php bin/magento setup:install --base-url=http://127.0.0.1/magento2/ \ --db-host=localhost --db-name=rock --db-user=root --db-password= \ --admin-firstname=Magento --admin-lastname=User --admin-email=user@example.com \ --admin-user=admin --admin-password=admin123 --language=en_US \ --currency=USD --timezone=America/Chicago --use-rewrites=1

Above command will install magento2 quickly than web interface.