Exposure, brightness, contrast, ... adjustments are camera specific and are provided by the camera drivers or the camera configuration web interface. ContaCam just shows what is given by the camera manufacturer.
For USB camera / capture card
Go to Camera Advanced Settings and press the Source button to display the driver provided dialog.
Note: some drivers do not store the set values; ContaCam can do nothing about that, please contact your camera / capture card maker.
For IP camera
Go to its web interface accessed through http://camera_ip_address from your web browser.