Guidance on COM usage

[glatzert]

I created a NativeMethods.txt containing a COM Interface and a COM class

CCertRequest
ICertRequest3

I see the generated interface and class, but now I fail to see how to work with it, since the class does not implement the interface.
I might be too young to know about working with COM (😉), bit I feel like it would be good to have some guidance about that in the docs.
If I get a hint how to use it, I might even write those docs myself.