1. Wait until all models are loaded and give permission for webcam and microphone.
2. Give a smile into the webcam and wait until the buffer for heartbeat detection is filled.
3. Click on “Start Record” button to start recording and on “Stop Record” button to stop recording.
4. optional: View data in the plot.
5. Click on “Show JS Arrays” or “Export CSV file”, to show the recorded data as Javascript arrays or to export them
    as a CSV/Excel file.
6. optional: Click on the “Start” button to reset all values and restart the app.