You can adjust your camera and audio settings in the Device settings menu. This menu can be accessed from the room lobby, or from within a live room.
If you are using the Evercast desktop app 3.0 or higher, go to the top menu bar and hover over your name. Then click on Device settings.
If you are using the Evercast desktop app 2.x or Evercast for Chrome, go to the bottom right of your app and select More. Then choose Device settings from the menu.
This will bring up the Settings menu, where you can configure your camera, microphone, and speakers.