Short answers, pulled from the story.
The Belgrade offensive took place from September 1944 to November 1944. The joint Soviet and Yugoslav forces liberated Belgrade on the 20th of October 1944 after eliminating thousands of surrounded German troops.
Marshal Fyodor Tolbukhin commanded the Red Army 3rd Ukrainian Front during the operation. Marshal Josip Broz Tito served as the Partisan commander-in-chief coordinating directly with Soviet leaders.
Parts of the 223rd Division and the 7th and 9th Serbian Brigade of the 23rd Division NOVJ liberated Bor on the 3rd of October 1944. This town held a large copper mine and housed some 1,700 forced laborers mostly Jews from Hungary who were freed during the operation.
Three Bulgarian armies totaling around 340,000 men stood ready on the Yugoslav-Bulgarian border in early October 1944. The Bulgarian 2nd Army included an Armored Brigade previously equipped and trained by the Wehrmacht.
The Medal For the Liberation of Belgrade was established by decree of Presidium Supreme Soviet on the 19th of June 1945. It was awarded to 70,000 Soviet and allied service personnel who took part in the battle.