Temperature based fan speed control using arduino

Please I need the complete code for this project, a temperature controlled fan using arduino
Working principle: the DHT11(temperature sensor) is set to sense the room Temperature between 20-28 degree Celsius, and send the data to the arduino which controls the fan speed accordingly, I need a calibration for fan speed of four steps, 20-22 (step 1- 25% speed) step 23-25(step 2- 50% speed) 26-28(75% speed) anything above that, the led comes on and the fan speed is 100% and below 20 degrees the fan goes off.
The temperature and speed per time is deployed on the Lcd screen.

Please I need the complete code for this project, a temperature controlled fan using arduino

The place to ask for that is in the Gigs and Collaborations section of this forum.