Check out what /u/SisterChenoeh says in response to "How did post-American Civil War black society compare to pre-emancipation black society?" and the book she suggests .

EDIT: See also Reconstruction: America's Unfinished Revolution, 1863-1877 by Eric Foner.

The first thing that many freed people did at the end of the Civil War was wander. One of the worst aspects of slavery was that family members were constantly separated with little way for them to contact each other. Now free, former slaves desperately searched for spouses, siblings, parents, children, that they had lost during slavery.

President Abraham Lincoln was assassinated in April of 1865, just a few days after the Battle of Appomattox, and before slavery had Constitutionally ended. Vice President Andrew Johnson took the Presidency while Congress was out of session. Johnson was committed to making all Confederate states accept the 13th Amendment, which ended slavery, if they wanted to become a state again, but he was still an ardent racist.

Johnson came from a poor family in Tennessee and jealous of the plantation owning elites his whole life. With his new reconstruction policy confederate slave owners had to get official pardons from him which would give them all their land back. Johnson loved having these Southern elites come and kiss his feet and Southern elites liked that they were getting their land back. Republican Congressmen were not happy with these changes at all so Johnson sped up his pardoning to end Reconstruction before Congress came back to session.

There were several attempts to get land for freed people, but none came through. During the Civil War the Union occupied Confederate land with plantations that had been abandoned by the white owners. Famously General Sherman made his Special Field Order No. 15 granted a huge swath of land along the South Carolina and Georgia coastline to the freed black population, but didn't give land titles.

When Congress finally began its session in December of 1865 there were several Radical Republicans that pushed for legislation for freed people, but they faced resistance from more conservative members of Congress and President Johnson.

The Bureau of Refugees, Freedmen and Abandoned Lands was created in March 1865 and was only legislated to last one year. So the new Congress's priority became to extend the Bureau. In this extension was a provision to grant all freed people the chance to lease 40 acres for three years and then buy the land.

That section about 40 acres turned into the promise of "40 acres and a mule" very quickly in within the black community many thinking that they would be given land in the turn of the new year.

Around this time Radical Republicans in the House, George Washington Julian and John Rice, tried to create their own legislation to grant land to freed people. Julian originally introduced a bill in 1864 to grant Southern land to Union soldiers or people that worked for the Union Military, but it did not make it out of the house. In January of 1866 Rice introduced the Southern Homestead Act, which allow non-confederates access to public land in the south similar to the Homestead Act of 1862.

Johnson vetoed an extension to the Freedmen's Bureau twice before Congress was able to override his veto with a compromised extension in July of 1866. In the meantime Johnson had returned almost half a million acres to former confederates, including all the lands covered in Sherman's Field Order.

General Oliver O. Howard was in charge of the Freedmen's Bureau, and despite him wanting to help freed people his hands were often tied because of legislation and lack of funding for the Bureau. Freed people did not have the money to lease land, buy farming implements, or travel to potential homesteads. General Howard was forced to try to get freed people to sign one year labor contracts with white plantation owners, often their former masters. This is also the time we begin seeing sharecropping programs begin.

Representative Thaddeus Stevens tried to introduce a bill that would take land from former confederates to give to freed people in 1867, but by then he saw no support even from fellow Republicans who thought that freed people should "earn" their land.

Many freed people did become trapped on their former plantations because they were forced to enter land contracts or sharecropping programs because they lacked other options, but the stories of freed people staying with their former masters often come from later lost cause writers who characterized black people has simple people who were more happy as slaves.

At the end of the Civil War freed people had little options to start their new lives and while there were Radical Republicans that tried to grant land to freed people these legislation faced considerable opposition in Congress and in the White House.

Sources

Eric Foner. Forever Free: The Story of Emancipation and Reconstruction.

Mark Summers. The Ordeal of the Reunion: A New History of Reconstruction

Mitchell Snay. Fenians, Freedmen, and Southern Whites: Race and Nationality in the Era of Reconstruction.

Douglas Egerton. The Wars of Reconstruction: The Brief, Violent History of America's Most Progressive Era.

Congressional Globe, the 39th Congress

To supplement u/SisterChenoeh and /u/lyle_lanly's answer, I'll offer that in addition to trying to find their families and places to establish communities of their own making, one of the first things on the post-empaciation to-do list was get an education.

During the war, schools quickly popped up in contraband camps as escaped enslaved people collaborated and worked for an education. There are first hand accounts from the wives and daughters of union officers about Black adults, including soldiers, and children who would take any reading material they could get their hands on. There were reports that Black soldiers that returned from patrol with books the found, the most coveted books being children's spelling primers. White and Black officers contribute to paying teachers' salaries and purchasing books and white and Black teachers traveled south, willing to help educate the newly freed enslaved people.

Every person with literacy skills was a teacher and as soon as a previously enslaved person mastered basic skills, they became a teacher. Susie King Taylor, a teacher on St Simon Island in Georgia, wrote about the formal and informal networks set up to provide resources to escaped people. These networks helped create schools that in some cases after the war ended, held classes nearly all day and all night. King wrote about elderly women learning next to their grandchildren, everyone committed to literacy, which was seen as an essential skill for participation in a democratic society.

More on the Freedman's Bureau and education here.