The main way in which the white Southerners attempted to limit black freedom in the years soon after the Civil War was through laws known as the Black Codes. Below are two links to articles about the Black Codes that give many details as to what those laws said.
One of the most important ways that the laws did this was to force blacks to work for whites. For example, Mississippi's laws said that blacks had to have a one-year contract by the start of each year to work for someone. They had to honor that contract. If they did not, they could be hunted down and forced to return to their "employers." It was also a crime to help any "runaway"--to give them food or shelter or help them to find a job.
By doing things like this, the white Southerners tried to ensure that blacks would be forced to work for them. There were other provisions that worked to limit the rights of blacks. Please follow the links to read more about them.