How did the black community know what to do during the Montgomery bus boycott?

There were about 40,000 African Americans in the city of Montgomery.

Black leaders had to make sure that they all found out about the plan. Nixon, together with Jo Ann Robinson, an English teacher at Alabama State College, planned the strategy for the boycott.

Fortunately, there were a lot of community organizations and churches, and everybody spread the word and helped out. Robinson printed up 35,000 anonymous flyers telling of Parks’s arrest and urging people not to ride the buses on December 5.

Within two days, the flyers were secretly passed around in black churches, stores, bars, and schools.