You can add a blog to your web page by clicking the 'Tools' link on the toolbar in the WebStarts page editor view and then choose 'Blog' from the drop down menu. The blog dialog box will appear. Create or edit a blogpost and then click 'Save'. You blog will be added to your web page. You can then drag and drop your blog where you would like it to appear.

Please note that the blog will expand as new posts and comments are left on it. Therefore it will make sense for your blog to be at the bottom of your page.