We Volunteers are great at answering basic questions. There is no FTP access to free hosted WordPress.com blogs and we bloggers cannot install any plugins. they are for WordPress.org installs only.
Please read this comparison for clarity on the differences between free hosted WordPress.com blogs and WordPress.org installs for self hosting http://support.wordpress.com/com-vs-org/
You will find a link to the step by step Learn WordPress.com blogging Tutorial prepared by Staff on the bottom of your Admin page. http://learn.wordpress.com/
The support documentation is all found at the Support link http://en.support.wordpress.com which is also on the bottom of your Admin page.