During the final days of the planet, Krypton, as it was moments away from destruction, scientist Jor-El and his wife Lara saved their newborn son, Kal-El, by sending him thru space via pod just before Krpyton secomed to to it's inner Nuclear explosion, leaving Kal-El to be The Lost Son of Krrpyton. The pod flew him all the way to Earth, in particular Kansas in the United States of America, where he would then be raised by the couple Martha and Johnathon Kent. From there they decided to adopt the orphaned infant by the new earth name, Clark Kent.
As time progressed, as a result from exposure to Earth's atmosphere (Particularly yelloy sun light) as oposed ot the original, Clark ben showing signs of Enhanced strength, speed, and other non-human abilities such as heat vision and even flight. From there the kents (Clark included) begin to learn more about Clark's Kryptonion origin.