Well,

I am not sure I get your question, but, the default blog block (actually using Page List) allows you to add as many blog entries as you want... Just use the composer (Dashboard->Write) or from the page directly add a Blog Entry (Edit -> Add Subpage -> BlogEntry) and entries will be displayed into the blog correctly.

Now, if you want to add two separates blogs on a website, just add a new subpage (out of the blog subpage), then add a Page List block to that page, configure it to only list subpages of that particular page which are of type "Blog Entry". This way you will have another blog, and you will only need to add your blog entries as subpage of the newly created Blog "root".