The orbiter has wings that create lift. For control, each wing has an elevon. An elevon is a combination of an elevator and an aileron. On most airplanes, the elevator is located in the tail section. The ailerons are found at the trailing edge of each wing.
Ailerons control an airplane's roll motion.
The split-rudder on the orbiter also works as a speed brake. It does this by splitting in half vertically and opening like a book. This deflects the airflow, increases drag, and decreases the orbiter's speed as it rolls along the runway upon landing. The airplane-like control surfaces on the orbiter are useless in the vacuum of space. However, once the orbiter re-enters the earth's atmosphere, these control surfaces interact with the air molecules and their airflow to control the orbiter's flight path.