Ok, I'm feeling stupid, which means I'm probably asking the wrong question.
I understand that in WordPress.com I cannot upload plugins and there is no plugins tab on my dashboard.
On the other hand, this support page says:
There are lots of plugins already bundled with every WordPress.com blog and website. They extend WordPress functionality and include things like Google Sitemaps, caching, Akismet anti-spam, Carousel slideshows, social media buttons, and over a hundred others.
So where are these plugins, and how do I access/use them? Or does this mean that WordPress.com has built-in features that would otherwise be provided by plugins?
Anyway, something here is unclear to me, and I don't like feeling stupid.
The blog I need help with is yossiswinepage.wordpress.com.