Tx and Rx simulation in CST

hi all, anyone can tell me how to simulate Rx and Tx in CST and what is the most wanted result?
i don't have any idea how to simulate it...do i need two port one for Tx and one for Rx? if yes how i want to know which one Tx because both has port..what parameter should i refer for Tx and Rx? where i want to se the Tx and Rx power?