I am creating a site and I need to use plugins, but on my dashboard there is nowhere to add my plugins for my site. How do I get it?
Wordpress.com does not allow you to install plugins.
From their Plugins support page:
Plugins are tools used to extend the functionality of the WordPress platform. However, they are only applicable to self-hosted blogs and web sites using the WordPress.org software. Plugins are not permitted here at WordPress.com for various security reasons.
If you require plugins, you’ll need to acquire your own hosting.
You cannot install plugins on wordpress.com. You have to create a WordPress Site with the software offered on wordpress.org.
If you don't know how to install WordPress, I would recommend to choose a Managed WordPress Hosting like MyWoHo, Wpengine or Websynthesis. MyWoHo starts at 3$/month. It's not much, if you wanto to try.