No Plugins Option on Dashboard

There is no “Plugins” option anywhere in my Dashboard, and I cannot figure out how to enable this function so that I can use new plugins to modify my website. (hosted with WordPress, 3.1)

I am learning all ‘how websites work’ stuff from scratch, so am having a hard time following some of the different commentaries on problems like this on other posts.

I did look in folder that all of the website files are located in on my hard drive and saw that under wp-content/ there is a Plugins folder and that looks like there are several plugins within that folder that the website currently uses.

And I really just don’t understand where to go from here to get a plugin tab so that I can use the dashboard interface to add plugins and modify them using the “visual” editing components that i currently use for modifying different elements of other pages i have access to.
Thanks.