Come to another world and become a lord

An ordinary person from modern society traveled to a fantasy world and became a serf. He thought that this life would end in a muddle, but because of a kingdom crisis, he was made a baron by the king, and even his background was tampered with to become a member of the royal family. He has a castle and land. Although he is just a small baron, everything can be developed slowly. Use your modern knowledge to change your fate...