How do I reset the Check Engine Light on a 2005

How do I reset the Check Engine Light on a 2005 Ford Taurus? The system check says everything is OK. Previously, a dirty air filter caused the light to come on. I replaced it (it was somewhat dirty.) but the light did not go out. Also, a couple of days ago, my "gas cap" and "Brakes" lights came on. I restarted and the fault was cleared. However, the check engine light came on later.