send and receive in socket programming c#

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C#

public void receive_send(object obj) {
           Socket sk = (Socket)obj;
           while (true) {
               Byte[] buffer = new Byte[1024];
               int recv = sk.Receive(buffer);
               foreach (Socket temp in listClient)
                   temp.Send(buffer, buffer.Length, SocketFlags.None);
           }
       }

I looked at an app chat, above code is on server.
I have some problems about send and receive method.

First, Receive means "receives data from a bound System.Net.Sockets.Socket into a receive buffer", so sk.Receive(buffer) mean receive data from sk ?
have any differences between it and ReceiveFrom method?

Equal problem with Send?
temp.Send means "send data to temp" ?

Here is link to all code.
https://www.dropbox.com/s/6z1u91hoh5utdb9/server.txt[^]
https://www.dropbox.com/s/wh0s7wml4aol7ze/client.txt[^]

Tks to read.