How do Client receive message from sever?

#1 What do you mean by 'how'?
-- how the function and call to it need to be configured?
-- how does it happen in the engine?
-- how TCP works? ;-)

#2 "How the function and call to it need to be configured" :p
Sorry, working on English by now.

#3 First of all you need to have a reference to the client's GameConnection object, call it %client

On the server, use a line of code like this:

commandToClient(%client, 'DoSomething', "hello", 1.2);

Then on the client, this invokes a function called clientCmdDoSomething:

function clientCmdDoSomething(%arg1, %arg2) {
   // code in here...
}

In my example, I have sent 2 arguments to the client: %arg1 receives the value "hello" and %arg2 receives the value 1.2

A very useful construct for invoking a function on all clients is:

for( %i = 0; %i < ClientGroup.getCount(); %i++ ) {
    %cl = ClientGroup.getObject(%i);
    commandToClient(%cl, 'NPCGangArrival', %name);
}

Here I'm telling all connected clients about the arrival of an NPC gang into one of my game's timetrial events

Hope that helps...

#4 This helps alot! Thank you!