As Phil says, URL Integration is how you use raw URLs to access DocuWare. If you want to use the Platform service, you need to use a request object, e.g. via the DocuWare packages in Visual Studio (C#) or the ServerXMLHTTP object that is part of the MSXML layer in Windows.
Here is a forum post about how I got the restful API working from Visual Foxpro:
You can also use a tool like Postman to play around with POSTs and GETs against the platform SDK. I didn't even know abou tthat tool when I started all this, so my journey was a lot of trial and error and shooting in the dark.
Hope this helps,