Powerpoint presentation about Build-Out Lines that Jack Deplitch commissioned for referee training in Virginia. I think it is pretty helpful, and since those mandatory US Soccer changes (U9-10 only) are going into effect this season for the first time, it may be worth bringing it to your referee’s attention.
Regarding build-out lines, a few points are worth emphasizing: First, the concept is highly controversial, and several clubs are asking their GKs to ignore it, meaning that they will be playing the ball before the attacking team retreats. This is not a problem, and even though the attacking team may end up stealing the ball away, the game should not be stopped merely because the GK played the ball before the attacking team retreated. The GK is entitled to wait for the attacking team to retreat, but it is not mandatory.