EShop category plugin is used to display the products list of a specific category in a Joomla article.
You should go to Extensions -> Plugins to filter "Eshop Category content plugin" and enable it.
Then go to edit the Joomla article and enter {eshopcategory 1} with 1 is the ID of category that you want to insert to that article. Now, if you view the article on the front-end side, you will see the list of products of that category there.