Step 1: Downloading!
-Download the mod itself (duh!) and hotfixes(Patch 2.1, Patch 2.2, DAC_Fix).
-It is not necessary to download the beta patch for ArmA2. Since the game was auto updated through Steam, this patch is not needed.
Step 2: Installation!
-Run the installer .exe.
-When prompted to enter the path to your root ArmA folder, navigate to "steam > steamapps > common > arma 2" and click okay.
-This will probably be found in C://Program Files or wherever you initially installed Steam.
Step 3: Patching!
-Open up hot-fix "I44-I44_ArmA2_v2-1" and drag and drop the @I44 folder into your arma 2 root we found earlier, as indicated in the readme file in the .zip.
-Now do the same with hotfix "I44_ArmA2_v2-2".
-Now drop the files from "I44-DAC-S-Fix.rar" into the Addons folder INSIDE the @I44 mod folder (there are no preset folders on this last patch).
Step 4: Shortcut...ing!
-You should still have your arma 2 root open, so find arma2 executable file.
-right click on it and select "Create Shortcut".
-Place the shortcut on your desktop.
-Right click it and select "Properties."
-In the field called "Target", paste -mod=beta;@I44 -nosplash outside of the quotation marks and click "Apply" and "Ok".
Bam, you are all set to play Invasion 44 on Steam. If you have any problems post em here.
*Note* It might be a good idea to rename the shortcut something like "Invasion44"