Short answers, pulled from the story.
Adolf Hitler issued Führer Directive 21 on the 18th of December 1940. This directive formally committed Germany to the invasion and renamed Operation Otto to Operation Barbarossa.
The name change invoked the memory of Holy Roman Emperor Frederick I known as red beard. German nationalists had glorified this medieval Crusader king since the 19th century claiming he would awaken to restore Germany during its greatest need.
The entire Axis force numbered 3.8 million personnel. These forces included upwards of 3 million German troops and approximately 690,000 Axis soldiers deployed before the campaign began.
The Axis Powers commenced the invasion at around 03:15 on Sunday the 22nd of June 1941. Air raids reached as far as Kronstadt near Leningrad and Sevastopol in Crimea that same day.
German forces captured Smolensk on the 16th of July 1941. The gap between Army Group Centre was finally closed by the 5th of August when upwards of 300,000 Red Army soldiers were captured.