How did the DC Comics Justice League get started? and also...?

The Justice League of America first formed due to an alien attack by a group called the Appelliax. The Appelliax dropped meteors on the Earth that unleashed a powerful alien. The first one was noticed by Martian Manhunter, who defeated the Appelliax monster and telepathically found out of another meteor that crashed in Carolina. When he arrived, the meteor started to turn him into a tree. Meanwhile, Aquaman noticed another meteor in the ocean. After defeating that monster, he also arrived at Carolina, where it also turned him into a tree. The same thing happened to Wonder Woman (who found a meteor in Paradise Island), Green Lantern (he found one in space that landed in Africa), and the Flash (he was in Europe at the time and found one there). They all eventually were led to Carolina for that largest meteor, but it all turned them into wood. They defeated the alien that turned them into wood using teamwork and learned there was one more meteor that landed in Antarctica, near the Fortress of Solitude. The five heroes rushed there to find Superman and Batman, who were already friends, defeating the final monster. They decided teamwork was what caused them to win, so they decided to form a league against evil.