How do I point to the correct resource?

package com.teamtreehouse.pomodoro.controllers;

import com.teamtreehouse.pomodoro.model.Attempt;
import com.teamtreehouse.pomodoro.model.AttemptKind;

import javafx.animation.Animation;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Label;
import javafx.scene.control.TextArea;
import javafx.scene.layout.VBox;
import javafx.scene.media.AudioClip;
import javafx.util.Duration;

public class Home {

  private final AudioClip mApplause;
  @FXML
  private VBox container;

  @FXML
  private Label title;

  @FXML
  private TextArea message;

  private Attempt mCurrentAttempt;
  private StringProperty mTimerText;
  private Timeline mTimeline;

  public Home() {
    mTimerText = new SimpleStringProperty();
    setTimerText(0);
    mApplause = new AudioClip(getClass().getResource("sounds/applause.mp3").toExternalForm());
  }

  public String getTimerText() {
    return mTimerText.get();
  }

  public StringProperty timerTextProperty() {
    return mTimerText;
  }

  public void setTimerText(String timerText) {
    mTimerText.set(timerText);
  }

  public void setTimerText(int remainingSeconds) {
    int minutes = remainingSeconds / 60;
    int seconds = remainingSeconds % 60;
    setTimerText(String.format("%02d:%02d", minutes, seconds));
  }

  private void prepareAttempt(AttemptKind kind) {
    reset();
    mCurrentAttempt = new Attempt("", kind);
    addAttemptStyle(kind);
    title.setText(kind.getDisplayName());
    setTimerText(mCurrentAttempt.getRemainingSeconds());
    mTimeline = new Timeline();
    mTimeline.setCycleCount(kind.getTotalSeconds());
    mTimeline.getKeyFrames().add(new KeyFrame(Duration.seconds(1), e -> {
      mCurrentAttempt.tick();
      setTimerText(mCurrentAttempt.getRemainingSeconds());
    }));
    mTimeline.setOnFinished(e -> {
      saveCurrentAttempt();
      mApplause.play();
      prepareAttempt(mCurrentAttempt.getKind() == AttemptKind.FOCUS ?
                      AttemptKind.BREAK : AttemptKind.FOCUS);
    });
  }

  private void saveCurrentAttempt() {
    mCurrentAttempt.setMessage(message.getText());
    mCurrentAttempt.save();
  }

  private void reset() {
    clearAttemptStyles();
    if (mTimeline != null && mTimeline.getStatus() == Animation.Status.RUNNING){
      mTimeline.stop();
    }
  }

  public void playTimer() {
    mTimeline.play();
  }

  public void pauseTimer() {
    mTimeline.pause();
  }

  private void addAttemptStyle(AttemptKind kind) {
    container.getStyleClass().add(kind.toString().toLowerCase());
  }

  private void clearAttemptStyles() {
    for (AttemptKind kind : AttemptKind.values()) {
      container.getStyleClass().remove(kind.toString().toLowerCase());
    }
  }

  public void DEBUG(ActionEvent event) {
    System.out.println("Hi Mum");
  }

  public void handleRestart(ActionEvent actionEvent) {
    prepareAttempt(AttemptKind.FOCUS);
    playTimer();
  }
}