As far as I know there are no official blog templates available for EPiServer 7 (therefore no documentation).
But the blog templates included in the EPiServer 5 and 6 public templates should still work for EPiServer 7 using the EPiServer.Blog.dll from EPiServer 7.
The blog post you linked at http://www.epinova.no/blog/jorgen-helgheim/dates/2010/4/episerverblog-setup-/ should be enough to get started, along with the comments in this thread: http://world.episerver.com/modules/forum/pages/thread.aspx?id=46135
Episerver.Blog.dll is shipped with Episerver CMS. Where can I found documentation or samples for Episerver.Blog?
Please don't provide solution with Community or Relate.
Good post is here http://www.epinova.no/blog/jorgen-helgheim/dates/2010/4/episerverblog-setup-/ but it's year 2010 and for Episerver 5. So it's obsolete.