Hook the gyro up to the analog inputs. In the control manual, it should tell you how. Assign it to one of the analog inputs, ex: analog3, in default code, sensor3. Turn the constant for sensor3 on, add it to your serin command, and input data from it. The yaw rate sensor, measures the rate of angular change from an arbitrary plane. So basically in the right position, if you turn it, the value changes. However, it resets starts recounting after around 60ms (3 pulses). This might help, heres our default code, it has some balancing code using gyros for the eduRobot.
Gyro Code -> sub_balance