If you want to grab a players name there's two ways of doing it.
PHP Code:
char name[MAX_NAME_LENGTH];
GetClientName(client, name, sizeof(name));
or you can do it like this
PHP Code:
PrintToChat(client, "Hello, %N", client); // %N is a shortcut for a player's name basically
If you want to make a connect message, you should probably use OnClientPutInServer is stead of OnClientConnect. The reason is, OnClientConnect is SUPER early in their connection stage so if you were to print something to them immediately when they click the server on the browser, they'd not receive it. OnClientPutInServer is basically once they've finished downloading and have entered the game.
Also, there's a difference between forwards and natives. Forwards are like events, something that happens. Natives are like functions. If you wanted to use OnClientPutInServer, you'd have to do this. Then every time the client is put into the server they have this printed to them.
PHP Code:
public void OnClientPutInServer(int client)
{
PrintToChat(client, "Hello, %N", client);
}