Many of them were effectively re-enslaved due to the loophole in the 13th Amendment that allows for those convicted of crimes to be enslaved.

Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.

The cotton still needed to be picked. Plantations didn't suddenly start to work just fine with fewer laborers, and plantation owners hadn't exactly budgeted in advance for "what if I need to start paying all 20 of these people?" There was high demand for forced labor. Between vagrancy laws and verb-while-black laws, they were able to come up with a supply to meet the demand.

I can't answer about schools, though.

After the war, a large number of abolitionists moved south and many began to run school for the formerly enslaved, however they were dismally understaffed, slave children were used in labour as the families needed to feed themselves. the union set up the Freedman's Bureau which was intended to make sure the former slaves were not taken advantage of and were given fair treatment. they built and tried to fund schools however they were understaffed and given insufficient funds to service the entire south. After reconstruction ended with the election of Rutherford B Hayes, the implementation of vagrancy laws, the eventual Jim Crow legislation, and the overall social milieu of a former slave, they were, in all but name, enslaved.

They were effectively re-enslaved through multiple means, primary of which was the development of the tenant farmer/sharecropping system in which the farmer borrowed the tools and supplies (if necessary) as well as rent the land to plant a crop. After the harvest the debt was paid off on the crop; however, a bad crop could continuously put a farmer in debt until they could not pay off their debt at all and were effectively tied to the land. Another means which developed further on after reconstruction was the use of prisons as a massive slaving business as men were arrested and rented out to companies as cheap labour. The saddest part of this was that while slavery was cruel, the life of a slave had value insofar as the master had paid a significant sum of money for them and would not want their investment destroyed unless absolutely necessary. Under this system there was always a fresh supply of bodies to work and in essence the value of a black life became minimal as the employer had no investment in their life.

In essence after the demise of slavery, the life of the southern black population became harder and their life became nearly meaningless. as slavery was reintroduced by the southern elite.

Edit: "Slavery by another Name" and "Let Us Now Praise Famous Men" are both good books on this topic, however the latter is written about the Great Depression however it gives a good idea of what sharecropping was like.

Okay going to start with work.

This varies quite a bit. The Freedman's Bureau is set up after the war to deal with labor mostly, but also other things such as law cases. Getting work for most freed people basically involved going back to do the same kind of work they had done before the war. Essentially was it formed is the contract system which was supposed to be negotiated by the Freedman's Bureau(didn't always happen). Basically they would sign on to work on x plantation for x pay a month. Sometimes it might include food, clothing, housing and other contracts might not include any of that.

Another type of contract is what we might call sharecropping. Basically former slaves would rent a piece of land from a plantation owner and often the seed/tools needed. This ran a lot of people into debt though as they needed to borrow money often. Sometimes they might pay the land owner directly in crops, other times they would sell them at market and then pay the owner.

I am not particularly well-read into schools, but a good number of former Union soldiers either stay or move South after the war and teach in freedmen's schools. These weren't funded very well from what I remember, I believe the Freedman's Bureau also ran these. The President tried numerous times to kill the funding for the Bureau so it made education a bit rough in the South.

They weren't treated well in most of the South to say the least. Reconstruction is pretty much the war being fought off the battlefields. Many places in the South such as New Orleans get very violent in the later years of Reconstruction. Shortly after the war ends it gets violent in New Orleans but eventually things cool down when most former Confederates are disenfranchised. By the 1870s the South gets very, very violent. Think small battles being fought.

Eric Foner's Reconstruction is a very good overview for this sort of stuff.