importerror - how to understand dot notation in this Django blog app -

i learn book python web development django covers django 1.0 . on other hand, use django 1.5.1 , python 2.7.5 . stuck @ 'making blog's public side' session.

i open blog/views.py file , type following:

from django.template import loader, context django.http import httpresponse mysite.blog.models import blogpost  def archive(request):     posts = blogpost.objects.all()     t = loader.get_template('archive.html')     c = context({ 'posts': posts })     return httpresponse(t.render(c)) 

next step, edit mysite/urls.py looks this:

url(r'^blog/', include('mysite.blog.urls')), 

and last step, make new file, mysite/blog/urls.py, containing these lines:

from django.conf.urls.defaults import * mysite.blog.views import archive  urlpatterns = patterns('',     url(r'^$', archive), ) 

but, when try open http://127.0.0.1:8000/blog/, arised exception value: no module named blog.urls. after doing research, found problem little bit similar mine. so, based on exception value, edit mysite/urls.py:

url(r'^blog/', include('blog.urls')), 

i refresh web browser, exception occurs : no module named mysite.blog.views. @ mysite/blog/urls.py file contains mysite.blog.views , edit it: from views import archive. refreshing browser.

and...i 'oh ok..' when saw no module named mysite.blog.models. edit from mysite.blog.models import blogpost from models import blogpost. finally, blog appears in browser.

my questions :

1. what technical explanation i've done , exceptions occur? i'm guessing edit other 2 files (the first 1 because see solution research). example, difference between url(r'^blog/', include('blog.urls')), , url(r'^blog/', include('mysite.blog.urls')), ? in beginner opinion, both true (even in first time, last 1 more 'complete')

2. are these problems related django version use (1.5.1), book use django 1.0?

sorry long post want understand these stuff in detail. thanks!