I would like to suggest stickies "That question has been answered 7,000 times at least here. Not to be rude," on most searched quarries. I know some are put in bold but would like it more easier like New players here ? thread.
Stickies:
HowTo: Play downloaded Coop and Single Player maps in the editor and edit them.
HowTo: All your question and answers (Video, step by step) for Mods.
HowTo: Play and Host on your own computer with ArmA2.
This is being done by some great ArmA community players which has helped me a great deal. But needs it's own AREA: New Players Here.