How do I add meta title/description and intro text to a Channel index page? I've created a Channel with templates blog/index and blog/_entry. Template blog/index will list the blog articles and blog/_entry will display individual blog articles. I want to have meta title/description and some intro text on the blog/index page that is managed by Craft. How can this be done?
From the docs:

Singles

Singles are used for one-off pages that have unique content requirements, such as:


home page
an About Us page 
a Contact Us page


Unlike the other section types, Singles only have one entry associated with them, and they don’t have an editable Author, Slug, Post Date, or Expiration Date.



So create the fields you need, create a new single for your index page, add the fields to the single, set the single to load your index template, then code your new fields into the template