Would somebody PLEASE explain the electoral college and win a $10 amazon gift cert!?

Please, please make it simple. Pretend you're talking to a third-grader here. I want to learn why we have the EC and whether it is FAIR and correctly represents the American vote. Also, would it make sense to have the electoral college when electing senators and representatives, but NOT the President, and if so, why? Whoever teaches me best about this will be my HERO AND I will send you a $10 amazon gift certificate. NO KIDDING. Thank you, friends.