Right before the 20's started World War I happened, so many of the young men of the world were apart of that war and saw horrific things. So after the war they wanted to forget so they had as much fun and parties as they could.
I wont write you a 4 paragraph essay, but what I will do is give you some advice. When you're writing an essay, the paragraphs don't have to be massive. You can use 4 sentences, and it will be considered a paragraph. Add the basic information it wants, and no more. Good luck!