put the robots.txt file in the document root directory for for the hostname in question. all well-behaved bots will request the /robots.txt file before attempting to crawl any other urls.
12:52 pm on Nov 7, 2012 (gmt 0)
The robots.txt file is placed in your www or public directory.the correct location where to put this file is in www.yourdomainname.com/robots.txt. This file indicates how deep the spiders can crawl into your website.
7:35 pm on Nov 7, 2012 (gmt 0)
It's robots.txt not robot.txt
It will only be read if it is in the root folder of the website.
Upload it via FTP and you're done. You don't "submit" it anywhere.