EDI order to Sales Order in SAP By Design

Hi,

I would like to understand, how the EDI customer order is going to become SALES ORDER in SAP by Design ERP system?

We are suppose to use AS2 channel between us and VAN provider. What is the suitable document type, which is supported in SAP By Design for sending and receiving messages from and to our VAN partner.
I have read article "integration scenarios of B2B communication", and Integration enablers and OPEN APIs, but not really understand how its gonna work together.

https://help.sap.com/doc/saphelp_byd1705_en/2017.05/en-US/PUBLISHING/IntegrationScenarios.html#BusinesstoBusinessSalesOrderIntegrationwithCustomers

What is necessary to set in ByDesign environment, and what is needed to be developed? Could someone explain it step by step.

Thank you for your answers.

Regards,

Norbert