After ancient people finished writing books, how can they sell them to make money?

There were booksellers in ancient times, and they were also workshop-style. They will collect and print marketable manuscripts, and they will also pay for them. A book that sells well will be secretly reprinted by other booksellers, which is ancient piracy. Ancient pornographic books and periodicals such as Jin Ping Mei are also privately printed underground, and the official should check it out.