Short answers, pulled from the story.
SS-Sturmbannführer Alfred Naujocks led the Gleiwitz incident under direct orders from Reinhard Heydrich and Heinrich Müller. The team planned and executed the raid from Sławięcice Palace, also known as Schloss Slawentzitz.
The Gleiwitz incident served as the primary justification for invading Poland during a speech in the Reichstag. Germany launched Fall Weiss or Case White on the 1st of September 1939 just one day after the attack at Gleiwitz to create a propagandistic casus belli for war.
The Gestapo executed Franciszek Honiok a 43-year-old unmarried Catholic farmer from Upper Silesia who was dressed to look like a saboteur before being rendered unconscious by drugs. Several prisoners from the Dachau concentration camp were also drugged and shot dead on site with disfigured faces to make identification impossible.
Britain and France declared war on Germany on the 3rd of September 1939 following the invasion. The European theatre of World War II had begun by that date despite global skepticism regarding the German version of events.
Der Fall Gleiwitz appeared in 1961 directed by Gerhard Klein for DEFA studios while Operacja Himmler followed in 1979 as a Polish film covering the same events. Die Blechtrommel released in 1979 briefly included the incident within its narrative and Hitler's SS: Portrait in Evil from 1985 also featured a short segment about the attack.