C++ doesn't have a built-in GUI library, so you have to find one that supports the platform that you're working on (e.g., Windows).
C++ doesn't have a socket library either, though one was proposed for C++20. I don't know if it was accepted, but even if it was, it might be a while before it's available on your platform. You therefore have to use something platform-specific again, such as
winsock2.h
on Windows.
I don't write GUI apps, so I can't help you there. But if you're working on Windows, you can find lots of TCP stuff in my
GitHub repository[
^], specifically in the
nw directory.
I'm guessing, though, that you're trying to take on too much, based on your statement about being really lost. This is not a project for someone without a reasonable amount of experience.