How do I set targets for the Helicopter in battlefield 4

I think he means lasing targets for the helicopters with a PLD. The Portable Laser Designator is a recon only gadget, which you start your recon class with it. All you do is hold the aim or fire button (can't remember which) to bring the PLD to your eyes, then it's cross hairs to your target, which can be any enemy vehicle that has an enemy in it. You must keep the lock on it for the person firing the missile, say the heli pilot, to get a hit on the target. Almost all the RPGs in the game can lock on to laser designated targets, and any vehicle that has a missile that can lock onto vehicles can too.