Add code in ??? import javafx.application.Application; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.control.Button; import javafx.scene.control.Label; import javafx.scene.control.TextField; import javafx.scene.layout.HBox; import javafx.stage.Stage; 

public class Viewer extends Application { /* board layout */  private static final int SQUARE_SIZE = 60; private static final int PIECE_IMAGE_SIZE = (int) ((3*SQUARE_SIZE)*1.33); private static final int VIEWER_WIDTH = 750; private static final int VIEWER_HEIGHT = 500; private static final String URI_BASE = "assets/"; private final Group root = new Group(); private final Group controls = new Group(); TextField textField; /**  * Draw a placement in the window, removing any previously drawn one  *  * @param placement A valid placement string  */  void makePlacement(String placement) { ???????   } /**  * Create a basic text field for input and a refresh button.  */  private void makeControls() { Label label1 = new Label("Placement:"); textField = new TextField (); textField.setPrefWidth(300); Button button = new Button("Refresh"); button.setOnAction(new EventHandler() { @Override public void handle(ActionEvent e) { makePlacement(textField.getText()); textField.clear(); } }); HBox hb = new HBox(); hb.getChildren().addAll(label1, textField, button); hb.setSpacing(10); hb.setLayoutX(130); hb.setLayoutY(VIEWER_HEIGHT - 50); controls.getChildren().add(hb); } @Override public void start(Stage primaryStage) throws Exception { primaryStage.setTitle("StepsGame Viewer"); Scene scene = new Scene(root, VIEWER_WIDTH, VIEWER_HEIGHT); root.getChildren().add(controls); makeControls(); primaryStage.setScene(scene); primaryStage.show(); } } 

This is all the code!