Webservice creation from FM

Hi Gurus,

Our external system want to check the sales order status in SAP via webservices.

I don't have a clue about WS's 😔

Do anybody have any really good manuals how to create the web service from function module? Is there any customizing behind that, what to set in SAP to use this web services?

I want to call from the external system SAP function BAPI_SALESORDER_GETSTATUS.

Thanks for any info,

BR

Saso