Problem Using Timer In Traffic Light Program

i want to make C# application that simulates a traffic light. That is, use the different Graphics methods (DrawLine, etc) to draw a traffic light, with red, yellow, and green lights. To make the application more interesting, provide three TextBoxes that the user can use to enter the number of seconds each light should stay lit. Place a Button on the Form to start the simulation with a green light. When the appropriate amount of time (according to the green value) has elapsed, the light should change to yellow. Once the time for the yellow light elapses, the light should change to red. Finally, after the light has remained red for the appropriate amount of time, the light should change back to green. Place a Button on your Form to allow the user to stop the simulation when they like to change the time values and rerun the simulation.

can some one help me plz :)