Child Busses

Hi, I don’t quite get Child Buses. I am setting up for a 5.1 mix. I want to be able to monitor on headphones in Stereo, so I thought adding a Child Bus to my 5.1 bus would let me do that. But it seems to monitor on the stereo bus, I have to select Stereo Out in the audio tracks Out put, which then stops it going to the 5.1 channels.

I’m confused, what use is the Child Bus?

Stewart Peters