Answer:
HE CAME TO EARTH IN A PAD (SPACE-POD), depending on the comic your reading, HE LANDED IN AMERICA OR RUSSIA
He was adopted by simple townsfolk who teach him the important human values - most importantly - the importance of helping others.
He then discovered a whole range of different powers at his disposal.
SUPER STRENGTH
Invulnerability
Heat Vision
Ice Breath
Distance Vision
Micro-Vision
Ability to Fly
X-Ray Vision
and a whole host of other abilities such as brain power, magic S and telepathy.
He is hurt by Kryptonite (or he loses his power when near it)
Superman has never actually done anything except infiltrate the hearts and minds of all those still young at heart. He is a symbol of hope and personifies the ideals on selflessness.
He is also a loner in a world where no one knows who he really is.
He has fought baddies and protected goodies for a very long time.