1. Drag the timer control onto your form
2. Give it a name
3. Go to the property called "interval" which will be the property for setting how often the timer fires an event. This is in milliseconds. So setting it to 1000 would be firing the timer event every second.
4. For the timer you will see an event called "tick". The tick event is the event that is called at the end of every interval time span of the timer. So if we have the interval every 1000 milliseconds it will fire the tick event every second.
In the tick event you can simply check how long a timer has been running or execute the incrementing of a variable etc and when it reaches a certain value, you close the form by unloading it.
Hopefully that helps you out.