Short answers, pulled from the story.
Soviet partisan numbers grew from more than 90,000 by the end of 1941 to 220,000 in 1942 and over 550,000 in 1943. These figures include both armed detachments and underground fighters operating in German-occupied territory.
The Central Headquarters of the Partisan Movement was established on the 30th of May 1942, headed by Panteleimon Ponomarenko as Chief of Staff and initially commanded by Politburo member Kliment Voroshilov. Before this, partisan units operated without central coordination or reliable supply lines.
Operation Rails War ran from the 3rd of August to the 15th of September 1943, involving more than 100,000 partisan fighters across an area 1,000 kilometers along the front. Partisans reportedly destroyed more than 230,000 rails along with bridges and trains, seriously disrupting German logistics for the Battle of Kursk.
Sydir Kovpak led the Putivl partisan detachment on extended raids from the Briansk forests through eastern Ukraine and into the Carpathians. His Sumy partisan unit covered more than 10,000 kilometers and destroyed garrisons in 39 populated areas, prompting German General Staff members to suggest Hitler consider using poison gas against partisans.
Relations between Soviet and Polish partisans broke down following the discovery of the Katyn massacre and the resulting rupture of Soviet-Polish diplomatic relations in April 1943. On the 23rd of June 1943, Soviet leaders ordered partisans to denounce Polish non-communist resistance units to the Nazis, and Soviet units were authorized to shoot Polish partisan leaders and disarm their forces.
Russia celebrates Partisans and Underground Fighters Day on June 29, established by the State Duma in March 2009 and signed into law by President Dmitry Medvedev on the 11th of April 2009. Ukraine marks the Day of Partisan Glory on September 22, first placed on the Ukrainian calendar in October 2001 after an order from President Leonid Kuchma.