Adam was the first man to live on Earth, created on the sixth day of creation. God created him from the dust of the ground, and placed him in the Garden of Eden. God told Adam that he could eat any fruit from any tree except one; the tree of the knowledge of good and evil.
When God saw that it was not good for man to be alone, he created Eve, who is the first woman. She was tempted by Satan (Satan was in the form of a serpent at this point) to eat from the tree of the knowledge of good and evil. She took and ate of the fruit. She then gave some to Adam, and he ate some too.
Because of his disobedience, God told Adam that he would have to work hard for his food, eating bread by the sweat of his brow. To prevent Adam and Eve from eating from the tree of life so that they would live forever, God drove them out of the garden of Eden. After he drove them out, he placed on the east side of the Garden of Eden cherubim and a flaming sword flashing back and forth to guard the way to the tree of life.
Because of Adam's disobedience, all of mankind are born into sin thereafter.