While the Cluster acts as a central place to manage connection-level configuration options, you will need to establish a Session instance to perform actual work against the cluster. This is done by calling the connect() method on your Cluster instance. Here, we connect to the contacts keyspace:

private Session session; // defined at class level
session = cluster.connect("contacts");

Once you have created the Session, you will be able to execute CQL statements as follows:

String insert = "INSERT INTO contact (id, email) " +
  "VALUES (" +
  "bd297650-2885-11e4-8c21-0800200c9a66," +
  "'[email protected]' " +
");";
session.execute(insert);

You can submit any valid CQL statement to the execute() method, including schema modifications.