Standard Pages/Blog notes: This is where you will select the "standard pages" and the content of each page. You can enter HTML. You can enter notes about the page. The tag used in the themes are within bracket.
About: You should use this page to write about you or what the blog is about.
Contact: You might want to write what types of email that you will reply too. If it's secondary blog, you might want to warned them that you might take weeks to reply.
Privacy Policy: You should write what you will do with the emails you received from the Contact page. If you use third party scripts, they might require that you warned people of what can be done with their information.
Blog notes: You can also enter notes about the blog like other passwords, task to do, third party scripts...