There is a great deal of information on the internet regarding how to employ artillery in various settings within the game, and no resource is more in depth than the Artillery Module wiki document which goes into exhaustive detail about how to set up artillery as real, virtual or with the Secop Manager. In my honest opinion the level of detail provided is overwhelming and difficult to follow.
All you need is contained in the base game and there is no need for any script (other than a bit of code that you can copy from this post and paste into a trigger in the editor) or third-party modification. To employ effective and realistic artillery in the game, what you need is five components that can be setup from within the editor: the player, an artillery module, a weapons system, a trigger and finally a marker.
The player is the simplest part as this is your character within the game world. You can be a warlord, a midwife, a tank or even a damn cow if you wanted to (seriously).
The Artillery Module
In this example, we are going to use Modules (F7) from within the editor and select an Artillery Module to place on the map, which will be named M1 (but you can name it COW1 or MOO1 if that fits the bill). The module will need to be synchronized (F7) to the leader of the weapon system group (not grouped F2 to that unit).
The Weapon System
Now this is where it can get a bit tricky as you have to select a weapon system that can fire an artillery round (a cow would not work). For the stock Russian forces that come with the core game, this would be a BM-21 Grad (under cars of all places), a D-30 or a Podnos 2B14 (both are under the static section).
Once setting the weapon system, you can add to it as long as you group the other units to the leader (which as mentioned above should be synchronized to the Artillery Module). To reduce the risk of unpredictable behavior from the AI (you will be using manned vehicles and equipment, not empty ones) from within the Edit unit panel set the Special setting from “In Formation” to "None".
Furthermore, if using a vehicle based weapons system, add the following code to the Initialization field:
Do that for every vehicle in the group.
This is perhaps the most important part of the whole setup as it tells the game engine what to do when the specified condition is met. In this example (and in the sample mission provided below) that condition is Radio Alpha, simply the player issuing the radio command from within actual game play.
The following code is to be entered in the On Acct. field of the Edit trigger panel:
[M1, getmarkerpos "M1FM1", ["IMMEDIATE", "HE", 0, 30]] call BIS_ARTY_F_ExecuteTemplateMission; M1FM1 = true
M1 is the name of the Artillery Module, M1FM1 is the name of the marker explained below and HE is the round type. For additional information and options available, please refer to the wiki link provided above.
Using Markers F6 from within the editor, you will place an aiming point for the AI. In this example I am using an empty marker named M1FM1 and placing in on some sexy infrastructure type stuff I want to blow the hell out of. If you wanted you could use any marker type, it does not have to be empty.
In the sample mission provided there is also a red round marker around the target area so that there is a visual representation on the map (empty markers do not appear on the map during game play, only in the editor).
And that is pretty much it. Here are some Fraps/YouTube videos I took for your enjoyment before you play the sample mission.