Allow WordPress site ( created from WordPress Network ) have its own registered users, and these use

Hi good day,

I have a WordPress Network installation and I have created a few sites with it.

There is 1 site in particular which I want it to be able to allow its own registered users, and these users can only read the posts of this blog in which they have registered for.

At the sametime, once the above privacy settings has been set, I want to allow new readers to register for this blog.

May I know what are the settings I need to adjust in order to achieve the above?

Best Regards.