The main idea/important event in Gn 11 is that all the people migrate to find a place to build heaven and then God came down and change all there language because it was a sin to just make your own you had to die first then go to heaven. The first thing that happens is that the people move to this valley in shinar and thought let's make a city and tower and they made themselves a city and tower. Next God saw and then he came and made everyone speak a different language. Finally God scattered them all across the earth so they would not build the city and that's how it got the name Babel. A life lesson we can learn from this passage is you should not cheat your way to certain thing.
"When they were migrating from the east they came to a valley in the land of Shinar and settled there. They said to one another, come let us mold bricks and harden them with fire"(Gn 11:2-3)
Hey...Lets build our own heaven!!
"Then the Lord said: If now while they are one people and all have the same language they have started to do this, nothing they presume to do will be out of their reach Come let us go down there and confuse there language so that no one will understand the speech of one another."(Gn 11:6-7)
"So the lord scattered them from there aver all the earth and they stopped building the city"(Gn 11:8)