If you want to you can download and install these files and play on the servers. Here is a little explanation of what they are what they do.
@cba_co
(Community Based Addons)
This file is needed in order for the following two mods to function correctly.
@jsrs
(Jarheads Sounds Redeployment System)
Basically, it changes the sounds of many in game items such as weapons, vehicles, footsteps, doors ... etc, etc. It is a rather large dowload but it makes all Arma 2 weaponry sound AMAZING!
@blastcore_visuals
(Blastcore Visuals - WarFX)
This mod is FANTASTIC!! Flames look real, explosions look real. When you shoot a weapon and the bullet strikes the ground, a puff of dirt and dust flies up from where the bullet struck. Flame shoots out the end of your gun barrel just like real life. Vehicle weapons look bloody awesome! Anything visual is pretty much updated in this mod.
There is also a batch file in the zip download that you can alter and use to join our PVE server. Just change the filepath in the file (by editing it with notepad) to your Arma 2 and Arma 2 Operation Arrowhead directory, set the IP and PORT to our PVE Server (because it's currently set to connect to the PVP one), double click on it and you are away.
It is a pretty big download but thoroughly worth it if you want the best experience out of your game. Just download it, copy the @cba_co, @jsrs and @blastcore_visuals to your Arma 2 Operation Arrowhead directory and set the batch file up. Easy.
The file is located here :
https://mega.co.nz/#!lpUh0Dyb!fH9ycIr7eHV9JnEsBGyXfW2hFGW1BsBuPHG0RJCLNzA
Any drama, just jump in the TeamSpeak server and someone will talk you though the installtion and setup. But it's not difficult.