Added the URL files to each app and updated the url and settings of the project.

stefan_gomez_music/About/urls.py

+from django.urls import path
+from .views import index
+
+urlpatterns = [
+    path('', index, name='index'),
+]
+
+
+app_name = 'About'
\ No newline at end of file

stefan_gomez_music/Contact/urls.py

+from django.urls import path
+from .views import index
+
+urlpatterns = [
+    path('', index, name='index'),
+]
+
+
+app_name = 'Contact'
\ No newline at end of file

stefan_gomez_music/Homepage/urls.py

+from django.urls import path
+from .views import index
+
+urlpatterns = [
+    path('', index, name='index'),
+]
+
+
+app_name = 'Homepage'
\ No newline at end of file

stefan_gomez_music/stefan_gomez_music/settings.py

@@ -37,6 +37,9 @@ INSTALLED_APPS = [
     'django.contrib.sessions',
     'django.contrib.messages',
     'django.contrib.staticfiles',
+    'Homepage',
+    'About',
+    'Contact',
 ]
 
 MIDDLEWARE = [

stefan_gomez_music/stefan_gomez_music/urls.py

@@ -14,8 +14,11 @@ Including another URLconf
     2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
 """
 from django.contrib import admin
-from django.urls import path
+from django.urls import path, include
 
 urlpatterns = [
     path('admin/', admin.site.urls),
+    path('', include('Homepage.urls', namespace='Homepage')),
+    path('About/', include('About.urls', namespace='About')),
+    path('Contact/', include('Contact.urls', namespace='Contact')),
 ]