Short answers, pulled from the story.
The Potsdam Agreement was signed on the 1st of August 1945 at Cecilienhof Palace in Potsdam. It was published the following day. The signatories were General Secretary Joseph Stalin, President Harry S. Truman, and Prime Minister Clement Attlee.
France was not invited to the Potsdam Conference. As a result, de Gaulle's government resisted implementing the agreement within the French occupation zone, refusing to resettle expelled Germans and blocking common policies in the Allied Control Council.
The Potsdam Agreement set the Oder-Neisse Line as Poland's provisional western frontier in Article 8, placing former German territories east of it under Polish and Soviet civil administration. The agreement explicitly stated that Poland's final western border should await a peace settlement, which did not come until the German-Polish Border Treaty of 1990.
The Four Ds were denazification, demilitarization, democratization, and decentralization. These principles governed the treatment of Germany in the postwar period and were executed by the Allied Control Council, which was constituted in Berlin on the 30th of July 1945.
The agreement authorized the transfer of German populations from Poland, Czechoslovakia, and Hungary, specifying that transfers be carried out in an orderly and humane manner. Expulsions occurred far beyond those three named countries, including in Romania, Yugoslavia, and Soviet-held territories, affecting Germans who had not already fled the advancing Red Army.
The Treaty on the Final Settlement with Respect to Germany, signed on the 12th of September 1990, superseded the Potsdam Agreement. That treaty resolved outstanding questions, including Poland's permanent western border, that the 1945 communiqué had left open for nearly 45 years.