Archives page
The archives page is an index of the whole blog: every published post, grouped by year and then by month, newest first. It is the counterpart to the blog listing — the listing is what you read, the archives are what you search by eye.
Set it up
Customize → Blog → Archives page. Pick a page and the index is built on it, under whatever the page itself says. Leave it unset and the site simply has no archives page — nothing is registered anywhere and no URL changes.
The dropdown can create the page for you if you have not made one yet. There is no page template to choose: the archives index is not in the template dropdown and not reachable through the template hierarchy — the theme hands the index to whichever page this setting names.
What else the page can show
Two checkboxes appear under the setting once a page is chosen. Both are off by default, which keeps the page as a plain index.
- Display all categories on the archives page — every category that has posts in it, listed above the index.
- Display popular tags on the archives page — the ten most used tags, each with the number of posts behind it.
Turn them on for a site with a real taxonomy behind it; leave them off for a blog with three categories, where the list says less than the index below it.
Writing on the page
Whatever you put in the page content is printed above the index. A sentence explaining what the reader is looking at goes a long way, and the page is an ordinary page, so anything the editor can do it can do.