Every Mykosmos/BOS application runs in 3 tier mode. Therefore, the programmer has to do nothing to give this capability to the delivered application.
The executable kosmos.exe that exists in the server runs automatically as a middle-tier Application Server.
The executables kosmos.exe that exists on the client machines run automatically as Clients of the above Application Server.
The required infrastructure to communicate the Application Server with its Clients is connectivity in TCP/IP (internet) between the machines.