Blogs can be created in a few different ways, and there are few different types of blogs to consider, depending on their use.
Creating a blog from the front end can easily be done using the Create Blog button on the blogs page.
Once this is selected you will note that you can create a blog that everyone can view, or you can selectively create a blog that can be viewed only by certain people. This can be handy if for example you have a blog only for your staff to see.
Entries and Importing from Feeds
Once a blog is created, you can add entries into that blog, but one important other item to note is that you can also create blog entries automatically from an rss feed if you wish to do so. In order to do this you would enter that blog, select manage block, and "Atom/RSS Import" as you can see below.
Once selected, you can then enter the details of your feed, in which entries will automatically be created.
From the admin CP, you can also create group blogs. These would be blogs that are created for use by various groups, but would show as owned by a group name. You can add these using the create blog button in Community>Blogs>Blogs within the admin CP.
From here you would then select the groups you wish to use this blog along with the owners name that will show.