How did Castro's rebels defeat Batista's army during the Cuban Revolution?

In 1952, Fulgencio Batista came to power in Cuba in a disputed election. At that point, Fidel Castro, an emerging figure in Cuban politics, started trying to overthrow Batista. Castro's rebel troops were defeated in a 1953 assault on the Moncada barracks. He and his brother Raul were put on trial and used the trial as a way to discredit Batista for grabbing power unfairly. As a result, Fidel Castro became a heroic figure in Cuba, and he was eventually released by Batista to Mexico. In Mexico, he continued to plot Batista's overthrow.

In 1956, Fidel Castro returned to Cuba with Ernesto "Che" Guevara and other members of the "July 26th Movement," which was named after the date they had attacked the Moncada Barracks. They gathered in the Cuban highlands, where Batista had a difficult time reaching them. There, they amassed followers and trained for Batista's overthrow. Batista sent troops to defeat the rebels, but his attack went sour, and it only attracted more soldiers to Castro's side.

In 1958, Fidel Castro attacked and defeated government forces in the plains of Cuba and in the city of Santa Clara. Eventually, in January of 1959, Castro's forces entered the capital of Havana and rooted out all the remaining parts of Batista's regime, and Batista fled Cuba. Later, Castro became a communist leader of the island.