There are two main options for setting up a blog.

Under Settings > Reading, if you select a page as your Posts page then it uses the standard blog template - there are some options for that under Appearance > Theme Options > Header & Sidebar > Blog homepage.

However if you want a Masonry style blog and/or more intuitive controls, we recommend not selecting the page as your Posts page, because then the page specific settings will work normally - the template and sidebar options.