Wliebelt, I think the first thing your supposed to do when unpacking the WSM is throw out the owners manual. /infopop/emoticons/icon_biggrin.gif Chris mentions that somewhere on this site. /infopop/emoticons/icon_cool.gif
I think it means to put down briquets to form a single layer--no briquets on top of one another. Two layers would be two briquets thick, etc. I don't know of anyone who actually cooks this way on the WSM. The methods described on the Firing Up Your Weber Bullet page are easier and work better anyway.