Held near Berlin, the Potsdam Conference (July 17-August 2, 1945) was the last of the World War II meetings held by the “Big Three” heads of state. Featuring American President Harry S. Truman, British Prime Minister Winston Churchill (and his successor, Clement Attlee) and Soviet Premier Joseph Stalin, the talks established a Council of Foreign Ministers and a central Allied Control Council for administration of Germany. The leaders arrived at various agreements on the German economy, punishment for war criminals, land boundaries and reparations. Although talks primarily centered on postwar Europe, the Big Three also issued a declaration demanding “unconditional surrender” from Japan.  The issues that had to be discussed at the conference were many. However, by the time of the finish, America had still not used the atomic bomb on Hiroshima so Stalin, with a huge military presence in the east of Europe, could afford to be forceful and confident of getting what he wanted. All Truman would say at Potsdam was that America had a weapon of awesome power – but that meant little to a leader who had millions of soldiers stationed in eastern Europe.  There are many sites giving information on this topic.
 
Text Sources
http://www.historylearningsite.co.uk/world-war-two/the-war-conferences/the-potsdam-conference/
See also
https://history.state.gov/milestones/1937-1945/potsdam-conf

http://www.history.com/topics/world-war-ii/potsdam-conference