Understanding "CPT Sidebars"

Hello,

I’ve created several CPT’s and notice I now have new CPT Sidebars.

However, I also noticed that only some of the CPT’s have sidebars. (see attached snapshot)

1. Why do some CPT’s have sidebars, and others do not?

2. How do I use these new sidebars? Is the idea that I add widgets specific to the CPT or CPT Category, and the CPT sidebars only appear on pages specific to those CPT listings? Need a little guidance to understand how to use them properly.

Thanks!