Why don't I have a plugins option on my dashboard?

If you are using a WordPress-hosted version of WordPress at WordPress.com (your site url will be similar to 'username.wordpress.com') then you are not able to install plugins. Only users with WordPress hosted on their own web host are able to install plugins. 

If you have a WordPress site at WordPress.com, you can still use Cincopa, you'll just need to follow these directions.