How to "copy the Oracle JDBC driver into sonarqube_extensions/jdbc-driver/oracle"?

I’m setting up Sonarqube according to Install the server and there I see a very strange instruction: a. Start the SonarQube container with the embedded H2 database: $ docker run --rm \ -p 9000:9000 \ -v sonarqube_extensions:/opt/sonarqube/extensions \ b. Exit once SonarQube has started properly. c. Copy the Oracle JDBC driver into sonarqube_extensions/jdbc-driver/oracle.** Where can I get JDBC driver and how to put it in sonarqube_extensions/jdbc-driver/oracle? Nothing. I don't know where to get JDBC driver and how to put it in sonarqube_extensions/jdbc-driver/oracle.