---
title: "Key steps"
url: "https://docs.adyen.com/point-of-sale/classic-library-deprecation/classic-library-integrations/com-extension-for-windows-integration/key-steps-com-extension"
source_url: "https://docs.adyen.com/point-of-sale/classic-library-deprecation/classic-library-integrations/com-extension-for-windows-integration/key-steps-com-extension.md"
canonical: "https://docs.adyen.com/point-of-sale/classic-library-deprecation/classic-library-integrations/com-extension-for-windows-integration/key-steps-com-extension"
last_modified: "2026-05-23T12:56:20+02:00"
language: "en"
---

# Key steps

[View source](/point-of-sale/classic-library-deprecation/classic-library-integrations/com-extension-for-windows-integration/key-steps-com-extension.md)

The cash register application must use these mandatory calls and callbacks to connect with the Adyen payments platform and process payments.

The key steps to integrate with the library are:

* [Initialize the library](/point-of-sale/classic-library-deprecation/classic-library-integrations/com-extension-for-windows-integration/key-steps-com-extension/initialize-the-library-com-extension)
* [Register the application with Adyen](/point-of-sale/classic-library-deprecation/classic-library-integrations/com-extension-for-windows-integration/key-steps-com-extension/register-the-application-with-adyen-com-extension)
* [Registering the PED](/point-of-sale/classic-library-deprecation/classic-library-integrations/com-extension-for-windows-integration/key-steps-com-extension/registering-the-ped-com-extension)
* [Process a basic transaction](/point-of-sale/classic-library-deprecation/classic-library-integrations/com-extension-for-windows-integration/key-steps-com-extension/process-a-basic-transaction-com-extension)
* [Cancel or refund a transaction](/point-of-sale/classic-library-deprecation/classic-library-integrations/com-extension-for-windows-integration/key-steps-com-extension/cancel-or-refund-a-transaction-com-extension)
* [Exit the library](/point-of-sale/classic-library-deprecation/classic-library-integrations/com-extension-for-windows-integration/key-steps-com-extension/exit-the-library-com-extension)