I'm new to GTD. I was a follower of Covey for years but some things just didn't work in real life. GTD has filled in those areas. However, I don't understand what David is advocating for a filing system. It seems he suggests 2: one for projects and one simply labeled A-Z. How does this work in real life? How do you file things in the A-Z system and then how do you find them again? I am ready to start my "in" box but I really need to understand this before I can empty it. Thanks.