What decisions were made at yalta, and what role did they play in the emergence of the cold war?

Yalta Conference In February 1945, Roosevelt had met with Churchill and Stalin at the Soviet city of Yalta on the Black Sea. At this Yalta Conference, the three leaders made a number of important decisions about the future. They agreed to move ahead in creating a new international peacemaking body, the UN, based on the principles of Atlantic charter. Stalin promised to enter the war against Japan after the surrender of Germany. He also promised free and unfettered elections in Poland and in other Soviet occupied Eastern European countries. They agreed on a charter. The charter created the general assembly, which was made up of all member nations and was expected to function as a town meeting of the world. The charter also set up administrative, judicial, and economic governing bodies. 

The Yalta Conference also displayed the deterioration in relations between the big powers. Roosevelt of America had died, to be replaced by strongly anti-communist Truman. Stalin felt that America were traitors for not telling the USSR about the invention of the Atomic Bomb, and in combination with Truman's strong dislike, this set the conference off to a shaky start. The British representative was Clement Atlee (I believe), and was weak in resolve and character, in comparison to Churchill who had been at the Potsdam Conference. This lack of strength allowed the Yalta conference to be dominated by Truman and Stalin, and arguments were common 
Where the 'Big Three' at Potsdam had suceeded, the new representatives failed to maintain healthy working relationships and as a result the Yalta Conference was not as successful as the Potsdam Conference and it gave an insight into the friction that was to come between the Soviet Union and the US.