Automatic generate standard XML sitemap for wordpress blog and add sitemap into current robots.txt. It's like XML feed.
No. The sitemap was defined as sitemap.xml. Your sitemap url should be http://yourblogurl.com/sitemap.xml
The sitemap is generate when it need. No file created.
You may custom the XML output with feed-sitemap.php.
No. It's will add your sitemap url into your robots.txt when plugin actived.