Configuring SinkWriter for h.264 with video and audio streams.

I'm trying to create a file using Media Foundation. I'm able to get what I need for video and configure it properly looking at MFCaptureToFile sample. I'm trying to do the same thing with audio from an audio source (mic or webcam). I set everything up properly and I do get samples, but I'm not clear on how to set up the output configuration for the audio stream. I do not have much experience with audio, so I'm not clear on which attributes I have to set, and which I can just copy from the input. 

Thanks.