The easiest way to add ambient sounds to a scene is through the use of an 'Audio Source'.
Photo reference. Further instruction below:
Go to your Hierarchy and highlight the Meeting Scene you'd like to work on. Right click the meeting scene and locate the Audio > Audio Source. Click to create.
In your Inspector tab, you will now be able to customise your Audio Source by dragging and dropping the desired sound WAV file into the 'Audio Clip' field and adjusting volume levels, in addition to a variety of other sound settings.
Tick the boxes 'Play on Awake' and 'Loop' if you want the sound to play for the entirety of the scene.