change statement with prepared statement in JAVA

I created the method to insert into database using statement. My schoolteacher asked me to changed to prepared statement to prevent SQL injection but I didn't understand how.

Here's the code that I wrote:

public void ajouterEntreprise(Entreprise e) {

    Statement stm;
    try {
        stm = cnx.createStatement();

        String query = "INSERT INTO `user`(`nom`,  `email`, `password`, `tel`,`role`,`offre`) VALUES ('" + e.getNom() + "','" + e.getEmail() + "','" + e.getPassword() + "','" + e.getTel() + " ', " + e.getRole().getId() + ",'" + e.getOffre() + "')";

        stm.executeUpdate(query);
    } catch (SQLException ex) {
        Logger.getLogger(ServiceEntreprise.class.getName()).log(Level.SEVERE, null, ex);
    }

}

Can anyone help me modify this to use a prepared statement?