How can specific module libraries be installed?

Hello,

      Based on my understanding, I have copied the 'bartik' theme folder from Drupal package to the 'themes' folder of my website, which otherwise was empty. Then I copied the 'superfish.js' file to themes>>batrik folder. If I understand correctly, the loading of 'superfish.js' should be specified in the bartik.libraries.yml file and simply having the .js file in the folder is not enough. However, it appears that I need to specify at a particular location and with an appropriate syntax, before saving and clearing the caches.

     I hope you could comment on where I can add the line in bartik.libraries.yml file to load the .js file. When I open this file, I see the attached format. Could you give me a syntax of the new line to be added?

Thanks again.