This is the info…
http://codex.wordpress.org/Template_Tags/get_calendar
but to save you all from having to go to a different page, I shall explain it here.
You simply need to add a line of PHP code to the template. The code is:
< ?php get_calendar() ? >
The steps:
1. Go to the admin section of WordPress.
2. Presentation
3. Theme Editor
4. Sidebar
5. Find where this part of the code is:
< ?php wp _list_pages('title_li=< h2>Pages< /h2>' ); ? > < li>< h2>Archives< /h2> < ul> < ?php wp _get_archives('type=monthly'); ? > < /ul> < /li>
6. and add the calendar code before the wp_list_pages junk.
7. update the page and BANG! You’ve got a calendar.
*Be aware, I had to add some spaces in the above code so that it would show up properly.