To update your bluetooth/microphone/speaker settings, click on the camera icon to open the recording window.
Tap on the gear icon next to the record button
Mobile
Desktop
Select the appropriate camera (including virtual cameras) and microphone that you'd like to use
Desktop
Mobile (iPhone)
If a webcam or microphone isn't showing up that you expect to see there, try restarting the computer or phone, unplugging and plugging back in the camera/microphone, and checking again.