Can you describe what should happen when you click the button? All you said was add time. You want to add a second, a minute, an hour, a day, a week, a month, a year? Are you going to create a text field where anything can be typed or have a dropdown menu with set amounts to be added?
The more detail you can give, the more responses you will receive. Also, it is a much better learning experience for you if you attempt to create the code to accomplish the task. That way, we can see the direction you are heading.