In our last configuration step, we want to go into the Advanced Audio Properties in OBS. When there, we want to set the audio sources we want to output have its Audio Monitoring setting be set to Monitor and Output.
If you intend to feed audio from OBS back into an VDO.Ninja group call, you can use this step to also mix-minus the audio; selecting just the audio sources you want the remote guests to hear, excluding their own audio to prevent echo.