Set up Audio sharing

Windows

On Windows, click on the caret above the mic icon within a call and select to share system audio. That's it!

There are a few steps to go through:

Install the Blackhole by downloading and running the installer. Here's a link to download it.
Once you've installed the extension, you need to create a new audio device that outputs both to the extension & your existing audio.
Launch the Audio Midi Setup app (comes built-in with MacOS).
Click the plus icon on the bottom left.
Select Create Aggregate Device
Select the Blackhole Box
Also, check the device you want to use as your speaker. (e.g. headphones, AirPods, speaker)
To use the newly created device go the the Speaker icon on the menu bar and choose Multi-Output Device.
To start sharing with Cosmos, join your Cosmos Office. Then, click on the chevron ˅ by the microphone icon, and select Blackhole.