What happened in the first Indochina conflict (up to the point where there was the Geneva conference)?
What happened in this conflict was that the Vietminh fought the French until the French left Vietnam.
The Vietminh had been formed by Ho Chi Minh and others who were opposed to the French. Towards the end of WWII, the Vietminh fought against the Japanese who had taken Vietnam from the French. When the Japanese left, the Vietminh declared independence.
The French, however, still wanted Vietnam as a colony. With US support, they fought the Vietminh. However, the French were unable to win. French public opinion started to turn against the war while the Vietminh, helped by aid from China, remained dedicated to the fight. In 1954, the French finally left Vietnam after losing their garrison at Dien Bien Phu. This led to the Geneva Conference in which Vietnam was split into two countries.