Thanks, @LanderU for your kind help.
My another question is, as I am connected with Brain's Wifi. is there any way I could control more than one copter with a single laptop? Actually, my plan is to control the swarm of copters with the single ground station. how can I make it sure that I control the individual drone? One idea that I have is, I change the Brain's AP mode to client mode. And connect all my copters to my router. And control them individually. What would you say about that?