The main idea/important event in Gn11 is that people tried to build a tower that would go to heaven and the people would communicate to form it. God said it was a sin to do such a thing and took away communication. The first thing that happens is that the people wanted to build a tower that would reach the sky. And started to built it the tower by communicating and with bricks and fire. Next God came down to see what the people were doing and said it was a sin to built a tower to heaven. Finally God decided to doing and mixed up there talking skills so that they could understand each other.
“The Lord came down to see the city and tower that the people had built… come, let us go down and there confuse their language, so that no one will understand the speech of another.” ( Gn11:5-8)
“...they stopped building the city. That is why it was called Babel, because there the Lord confused the speech of the world. From there the Lord scattered them over all the earth. (Gn11: 8-10)
A life lesson we can learn from this passage is to us our ways wisely.