It would be using non-violent protest during the civil rights movement to demonstrate the broken and unfair system the government has discriminated them over the years they endured and demanded the same equal rights as whites do.
Direct action for liberation seems like a good answers since they want the government to hear them and take action to solve the issues ingrained in the government system. However, since the question is asking what they used as a model to expanded and further their desire for their same rights as white Americans do, they mainly civically protest and speak out to raise awareness on the racial problems the white were treating them at the time where it is more openly acceptable to justify discriminating people of color for the simplest things such as separation of schools for white and African-Americans, sitting at the back of public transportation's, unequal pay and etc. And the stigma of people of color, especially towards African-Americans on them being violent and uneducated hinders them more if most of them did not went to do civil protesting.
I hope this helps in some way since it has been awhile with me for history but i would be happy to try to clarify some things here on the answer i wrote here if you still don't understand some things.