How a Button can have more than one mouse click ActionEvent, then place data into objects, then places objects into List and display List in console?

Question

I've created a stage and scene application for java. This program asks the user to click a button that says customer info. Then a dialog pops up in the application window and has Labels and TextFields for customer info. Then user clicks ok and it stores the customer info into Person class object. I am trying to have the user enter the info more than once for different customers and store them into a List. I am unable to store more than one customer. This is what I have so far:

package application;

import java.util.ArrayList;
import java.util.List;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.GridPane;

public class Main extends Application {

    @Override
    public void start(Stage primaryStage) {

        final CustomerInfoPane custInfo = new CustomerInfoPane();

        primaryStage.setScene(new Scene(custInfo, 375, 250));
        primaryStage.setTitle("Customer Information");
        primaryStage.show();

    }

    public class CustomerInfoPane extends GridPane {
        Label firstNameLabel = new Label("First Name:    ");
        Label lastNameLabel = new Label("Last Name:    ");
        Label emailLabel = new Label("Email:    ");
        Label phoneLabel = new Label("Phone Number:    ");

        TextField enterFirstName = new TextField();
        TextField enterLastName = new TextField();
        TextField enterEmail = new TextField();
        TextField enterPhone = new TextField();

        Button enterInfoButton = new Button("Enter your info");
        Button okButton = new Button("    OK   ");
        Button cancelButton = new Button(" Cancel ");

        CustomerInfoPane() {

            setVgap(10);
            setPadding(new Insets(10, 10, 10, 10));

            add(enterInfoButton, 0, 0);
            enterInfoButton.setOnAction(new EventHandler<ActionEvent>() {
                @Override
                public void handle(ActionEvent event) {
                    add(firstNameLabel, 0, 2);
                    add(lastNameLabel, 0, 3);
                    add(phoneLabel, 0, 4);
                    add(emailLabel, 0, 5);

                    add(enterFirstName, 10, 2);
                    add(enterLastName, 10, 3);
                    add(enterPhone, 10, 4);
                    add(enterEmail, 10, 5);

                    add(okButton, 0, 7);
                    add(cancelButton, 10, 7);

                    enterFirstName.setAlignment(Pos.CENTER_RIGHT);
                    enterLastName.setAlignment(Pos.CENTER_RIGHT);
                    enterPhone.setAlignment(Pos.CENTER_RIGHT);
                    enterEmail.setAlignment(Pos.CENTER_RIGHT);
                }
            });

            okButton.setOnAction(new EventHandler<ActionEvent>() {
                @Override
                public void handle(ActionEvent event) {
                    String firstName = enterFirstName.getText();
                    String lastName = enterLastName.getText();
                    String phoneNum = enterPhone.getText();
                    String email = enterEmail.getText();

                    Person person1 = new Person(firstName, lastName, phoneNum, email);
                    Person person2 = new Person(firstName, lastName, phoneNum, email);

                    List<Person> people = new ArrayList<Person>();
                    people.add(person1);
                    people.add(person2);

                    for (Person i : people) {

                    System.out.println(i);   //when this prints it print same data twice
                    }

                }
            });

            cancelButton.setOnAction(new EventHandler<ActionEvent>() {
                @Override
                public void handle(ActionEvent event) {

                }
            });

        }

    }

    public static void main(String[] args) {
        launch(args);
    }
}

This is my Person Class:

public class Person {
        private String firstName;
        private String lastName;
        private String phoneNum;
        private String email;

    public Person(String firstName, String lastName, String phoneNum, String email){

        this.setFirstName(firstName);
        this.setLastName(lastName);
        this.setPhoneNum(phoneNum);
        this.setEmail(email);

    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getPhoneNum() {
        return phoneNum;
    }

    public void setPhoneNum(String phoneNum) {
        this.phoneNum = phoneNum;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "First Name: " + firstName + "\nLast Name: " + lastName + "\nPhone Number: " 
                + phoneNum + "\nEmail: " + email;

    }

}

This is a picture of my panel with console output: