Currently in order to alter the colour scheme of the student facing screens you are required to alter the scripts /config/start.inc and /config/finish.inc. We will be looking to make the colour scheme configurable via the UI in a future release.
Logos are included on the student facing screens and the external examiner email.
These logos are stored in the theme directory (located in your rogo data directory) you can change the logos used by Rogo via the configuration admin screen:
misc_logo_email: logo used on external examiners email
misc_logo_main: logo used on student facing screens