Ok, So I am trying to make the ambient audio inside a building quieter than the ambient audio outside. How do I go about doing this?
The easiest way is to manually change the volume modifier in the sound cue.
Or you could make a sound class for Ambient_Interior and Ambient_Exterior and have them both playing without any attenuation / spatialisation. Without any edits they’d both sound the same but if you update your cues so that they’re associated with a Sound Class (left hand panel) then you can control them all in bulk 
That’s a lot easier if there’s lots of cues!