I saw this on the BI forums and thought it would be smart to post here as well for reference. Specially since we had many questions about this:
wrote an AI Squad Command Guide on the BI forums
Quote rotkeps :
This guide is intended to give a crash course into the essentials of controlling a squad in ArmA2. The UI, whilst pretty dire from an ease of use standpoint, is very functional, giving very in-depth control over the behaviour of your soldiers.
So a brief overview should set you on your way to becoming an awesome squad leader, though I would recommend throwing a squad into the editor to play around with and get comfortable with issuing commands before taking it into a fight, especially online.
It should be noted that not all menus related to controlling the AI will be featured, only the core set for controlling and modifying behaviour will be covered. Also I am not an expert on this, I merely have spent time in both the editor and in my much loved crCTI servers. You can find me playing on one of several of these crCTI (usually XR or AOD) servers under the name 'Dan' -- go easy on me though as I'm busy fiddling in menus controlling my squad
All Feedback welcomed!
Source: BI forums