I am a retired army officer. I served in the US army for about three decades. I have always wanted to publish my memoirs but the lack of time prevented me from doing so. Now that I have retired, I would like to share the various experiences I had while in the army, especially my account of the Iraq War in 1990-91. Though I do have in mind the substance of the book, I need help in putting it down. I require a guide for this.

OK... make your own chapter names, these are a little... basic.
Chapter One - Introduction
Chapter Two - How I Got Enlisted
Chapter Three - Boot Camp
Chapter Four - Shpping off to Iraq
Chapter Five - What happened there
Chapter Six - The end of the war

Chapter Seven - Final Thoughts
This isn't the best place for literary help, by the way.
This isn't you, is it?

... I don't really think that helped, michaelleung :D
And yes, this is not the best place to turn for help... Woudln't you be better off mailing experienced, professional writers?

what i recommend doing is this, write down everything that you can remember happened, and then figure out the order, and reorganize it as such.

Outlining helps as well. In the outline jot down the events that happened in the beginning and work your way down. Then using the outline you can fill in the rest of the details later. Outlines help you with organizing your ideas and they add structure to your work.

I would recommend putting as many gaming references into your account as possible.
Such as Abram Tanks should only be referred to as 'Land Raiders' and Chinook Helicopters as 'Thunderhawk Gunships'. Doing this would make any references to military hardware easier to understand for us geeky types.
Other than that, I would take Michaelleung's advice as he seems more switched on to narrative structure than the rest of us :)

I think your first step should be to decide what sort of structure you're interested in. If you want a chronological A-Z structure then Michaelleung's suggesion of a linear approach is probably a sound one.
If you wanted to do something a bit different, you could choose a structure that focuses more on emotions (fear, fun, anger, betrayal), types of events (heavy combat, post combat recovery, SAR missions, latrines) or something like that. That would allow you to use a more modular structure to your writing which may well speed the process and make an interesting twist to the usual structure.

I’d suggest you get hold of Adair Lara’s book, ‘Naked, Drunk and Writing’. Adair Lara, in her book, has guidelines for writing essays and memoirs. The book is a very instructive, practical and helpful guide on how to write memoirs, with lots of examples. It’s particularly good on how to “arc” or outline the memoir, to save yourself unneeded extra drafts in which you go in the wrong direction. . I think you can buy the book on-line from http://www.lulu.com/content/6105019. I am sure it will help you..

"War. War never changes."
That's enough.

Well publishers tend to prefer longer books over shorter ones, 4 words might not be QUITE enough.
It'd make a FANTASTIC chapter title though!