Well, it took me a while to figure out how to use the LD myself. Actually, I only figured it out like a few weeks ago
. But it actually is fairly simple.
First off, obviously you need to select the weapon, point it at the desired target, and then press fire. A little red dot should appear, and your sights will turn into a little diamond so you know you are firing.
The LD actually creates an "enemy" which is positioned on whatever the laser is pointing at. The A10 should be able to see this target with its radar when it gets close enough. You can also try right-clicking to try and reveal the target yourself. Then you just need to select the A10, and tell it to target the Laser Target (via the #2 menu), or else click on the target to tell the A10 to attack. Basically, the laser target will act just like an enemy that you can order the plane to attack via normal controls.
The A10 should drop its LGBs when told to attack this target. A10s will NOT fire missles at the target, from what I've seen. So I'm not really sure what types of weapons can and can not be targeted in this fashion, but the Laser Guided bombs work perfect.
That isn't a very good explanation, but once you see it in action, it will make sense.
Hmm... just thinking out loud here, but I wonder if you could modify the laser target that the LD spawns. Basically, if you could change it into something that ground soldiers would fire rifles at, then you would have an easy way to direct and order 'covering fire' from your squad mates. There might be some flaws, but I'm just thinking here...