Short answers, pulled from the story.
The Yalta Conference took place on the 4th of February 1945 at the Livadia Palace in Crimea. The resort town had been renamed Yalta after its Jewish population was stripped away to accommodate the meeting.
The agreement stipulated that the Soviet Union would keep the territory of eastern Poland that they had annexed in 1939. Poland was to be compensated by extending its western borders at the expense of Germany, which displaced millions of Germans.
Roosevelt and Stalin secretly discussed putting Korea into a trusteeship divided among the Soviets, the Americans, and the Chinese for a period of 20 to 30 years. They agreed that their troops should not be stationed in Korea, and the fate of the peninsula was not mentioned in the official records of demands and concessions.
The Soviet Union installed the communist Provisional Government of the Republic of Poland and conceded predominance of the pro-Soviet Lublin government. The final agreement was so vague that the Soviets could stretch the language without technically breaking it, leading to the establishment of totalitarianism in Poland by 1949.
President Franklin D. Roosevelt died on the 12th of April 1945, leaving Vice President Harry S. Truman to face the consequences of the agreements. Truman was kept in the dark about many secret deals and had to confront the reality that the Soviet Union was not honoring its promises of free elections.
The Potsdam Conference resulted in the Potsdam Agreement regarding the Soviet annexation of former Polish territory east of the Curzon Line. The provisions included the annexation of parts of Germany east of the Oder Neisse line into Poland and of northern East Prussia into the Soviet Union.