can't emit socket on server function.

[YureshMajhi]

I followed the documentation and it helped my connect the socket on the client side. I can see socket connection on the network tab but then the documentation just says one line.
socket.emit("hello", "world"); ??
what socket do i import from? the socket was created on server.js and then a seperate client socket for io. Now where did that socket.emit even come from. Why is there no proper explanation to how to emit the socket? do i really only get to use it on the api and not server function or what exactly? How do emit a socket in the NEXT.JS? is there any explanation at all?