1. Click on the three dots ( ... ) at the top right of the window
2. Click on "Settings"
3. Click on "Devices"
4. Make sure your Microphone is set to the microphone you would like to use, and your speaker is set to the audio device you would like to hear the other person from (You can click "Make a test call" to make sure you have the right microphone and audio device selected)
5. Scroll down to the bottom of the window. Make sure your webcam is set to the webcam you would like to use. You can preview the webcam in the preview window to confirm this.