I want to apply pivot to my site in the site library.

Hi there,

Using a child theme is optional, but it's easy to install: https://docs.generatepress.com/article/using-child-theme/

As for installing Pivot - take a look at our quick video on this page: https://generatepress.com/site-library

It highlights the process you need to take in order to install a site.

Let me know if you need more info :)

Thank you!

You're welcome :)