This trophy is called "CQ! CQ!" which requires you to give orders to an allied tank in the Command & Control Panel during a match.
During the course of any match, press the bottom right of the Touch Pad to bring up the Command & Control Panel. The C&C overlay will appear showing the list of allied tanks along with an A-I & 1-9 grid on top of the map. The map is the same map in the minimap on-screen during the match.
So, use Up & Down to select an ally and then push either L1 or R1 to change/give an order to that unit, unlocking the trophy.