The above code still applies,
since you are looking for a specific value from your sensor my assumption is that they would want it to be connected to an Analogue pin because it can read values from 0-1023. But then again maybe your sensor does not require the use of an analogue pin and can be attached to a digital pin. stepper motors aren't driven by degrees of rotation. They are driven by steps, different steppers can have different total steps per revolution, 200 steps is fairly common. So you will need to check to see what your motors is. Use the #include <Stepper.h> library in your code. You can find many tutorials on youtube and google as well as in the examples in the arduino IDE. you will also need a stepper driver to drive it most likely, the stepper A4988 is a good choice. Once you had set up your stepper and variables.
your code should have something along these lines:
analogueRead(sensorpin);
yoursteppermotor.Step(sensor pin Value * the number of steps to rotate the motor the amount you want for that temperature);