If you are talking about here, this isn't a blog site. This is a site for articles that are not purely personal. You will use your Start a Hub" button in the top of the right side of your screen.
Before you do that you'll need to read the learning center. http://hubpages.com/learningcenter/contents
If you were not talking about this site, sorry there is nothing I can really answer without more specifics since there are so many blog sites.