Django 2.0.1 won't launch index.html, how to fix?

Question

Django

Good afternoon!
I can’t run index.html, here are the screenshots with the code
, can anyone help with the problem?

spoiler

urlpatterns = [
    path('admin/', admin.site.urls),
    path('mainapp/', include('mainapp.urls')),

]

from django.urls import path
from . import views
urlpatterns = [
path('', views.index, name='index'),
]

Answer 1

You do not have a handler for the address in urls.pyhttp://127.0.0.1:8000/