When using Top Hat Community through a web browser you'll need to grant permission to use your webcam.
To start recording, click on the Create new Video Message option in the attachment menu, then click the red circle icon.
While recording, a stop button appears. To end the recording, press Stop.
Preview the video you recorded by pressing Ok. A window appears where you can watch, download, and name the video. To send the video, click Send or click Cancel to discard the video.