Socket Server - Accepting Multiple Clients (C++)

So I've made a server to accept clients into.
By doing so, I've noticed this works.
However, only one client is accepted.

I've read online, and decided I needed help.
Multithreading honestly confused me,
And I've saw posts on a continuous accept loop.

Upon this, it still doesn't work.
Would anyone like to help me on this topic?

Again, I'm trying to get it so I can open one server, and multiple people are able to join that one server.