Using the Smoke Grenade in AAO is relatively easy. All you have to do is pull it out and throw it buy press the fire key and releasing it. 4-5 seconds later it will start to smoke.
Cooking smoke grenades
Cooking a nade is one of the coolest things to do to surprise your enemy. When you cook a nade you are pulling the pin by pressing the fire and alt fire keys and holding the live grenade in your hand for a few seconds before you throw it by pressing the fire key. Usually the opfor you are throwing it at can hear you cook the nade and run away, but if you pull the pin before you are close to them they won't. A good rule of thumb is only cook it for 2-3 seconds because sometimes nades will have shorter fuses than others.
Airbursting a nade is a great technique to use to Smoke before it hits the ground and will smoke the air for a few seconds. You cook the nade like normal, but you throw it higher so that it will Smoke in the air over your target.
Silent grenade throw
If you want to throw a grenade without yelling, all you have to do is press the slow walk key before throwing it.
Probably the most useful to roll because of the fact that usually where you want to throw the smoke, it doesn't land there (Bridge Corssing is a great example!!). Instead of whipping that smoke where it might miss its intended target, roll the grenade. It will land reallllyyy close to where you want unless for some reason you get shot in the process of rolling it .. Rolling smoke is a very effective way to smoke a doorway, because when the smoke is thrown to the doorway, it tends to miss. You know what im talking about...