PWA - limiting access to part of a site

Hello,

Hello all. I was not able to find this topic in the forum.

I have a video library set up in my project site and I would like to grant access to certain people, but I do not want them to access other parts of the project site. There are unused groups like "Project Visitors" to which I could add people, but adding people here gives access to the entire site and I do not know how to set the permissions to limit them to just the video library.