Cannot convert textfield into string

Hi I'm currenntly doing a coding exercise where I create an application with 2 views. Create in it an application with two views. The first view should have a text field that's used to ask for the user's name. The second view then shows the user a greeting text. The greeting should be of the form "Welcome name!" where the user's name is inserted in place of 'name'.

package application;

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class GreeterApplication extends Application {

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

    @Override
    public void start(Stage window) throws Exception {

        //1. Creating the view
        //1.1 Creating components to be used
        Label intro = new Label("Enter your name and start.");
        Button start = new Button("start");
        TextField input = new TextField();

        //1.2 creating new layout
        GridPane layout = new GridPane();
        layout.add(intro, 0, 0);
        layout.add(input, 0, 1);
        layout.add(start, 0, 2);

        // 1.3 Styling the layout
        //1.4 creating view itself and setting it to use the layout
        Scene first = new Scene(layout);

        //2. Creating new view
        StackPane welcome = new StackPane();
        String name = input.getText();
        Label welcomeText = new Label("Welcome " + input + "!"); //inpu
        welcome.getChildren().add(welcomeText);
        Scene welcomeView = new Scene(welcome);

        //3. Adding event handler
        start.setOnAction((event) -> {
            if (!input.getText().isEmpty()) {
                window.setScene(welcomeView);
            }

        });

        window.setScene(first);
        window.show();

    }
}

I tried converting input into a string via input.getText() and input.toString() but I have had no success.

Kindly note the following edit.
Label welcomeText = new Label();
The text of the label should only be set after receiving the input from the user.
Hence, you can create a welcomeText Label and update its text value in the event handler using welcomeText.setText(input.getText()).