Germany wants Sudetenland because it was once Germany's land but got taken away during the Treaty of Versailles. German people live there and it is a good area because it has a great defense system with the mountains.
During the Munich conference Great Britain and France were scared Hitler would take over if he already took over Sudetenland. So in result both countries backed down because of too much power that Hitler had.
What Great Britain and France did was meet Hitler's demands which was called appeasement. But Hitler still had a stronger army then both these countries. This was because they both feared war. Hitler did not he went in right away and fought for what he had.